Soluble Zcytor11 cytokine receptors

ABSTRACT

Novel polypeptide combinations, polynucleotides encoding the polypeptides, and related compositions and methods are disclosed for soluble zcytor11 receptors that may be used as novel cytokine antagonists, and within methods for detecting ligands that stimulate the proliferation and/or development of hematopoietic, lymphoid and myeloid cells in vitro and in vivo. Ligand-binding receptor polypeptides and antibodies can also be used to block TIF activity in vitro and in vivo, and may be used in conjunction with TIF and other cytokines to selectively stimulate the immune system. The present invention also includes methods for producing the protein, uses therefor and antibodies thereto.

REFERENCE TO RELATED APPLICATIONS

This application is related to Provisional Application No. 60/223,827,filed on Aug. 8, 2000. This application is also related to ProvisionalApplication No. 60/250,876, filed on Dec. 1, 2000. Under 35 U.S.C. §119(e)(1), this application claims benefit of said ProvisionalApplications.

BACKGROUND OF THE INVENTION

Cytokines are soluble proteins that influence the growth anddifferentiation of many cell types. Their receptors are composed of oneor more integral membrane proteins that bind the cytokine with highaffinity and transduce this binding event to the cell through thecytoplasmic portions of the certain receptor subunits. Cytokinereceptors have been grouped into several classes on the basis ofsimilarities in their extracellular ligand binding domains. For example,the receptor chains responsible for binding and/or transducing theeffect of interferons (IFNs) are members of the type II cytokinereceptor family (CRF2), based upon a characteristic 200 residueextracellular domain. The demonstrated in vivo activities of theseinterferons illustrate the enormous clinical potential of, and need for,other cytokines, cytokine agonists, and cytokine antagonists.

DESCRIPTION OF THE INVENTION

The present invention fills this need by providing novel cytokinereceptors and related compositions and methods. In particular, thepresent invention provides for an extracellular ligand-binding region ofa mammalian Zcytor11 receptor, alternatively also containing either atransmembrane domain or both an intracellular domain and a transmembranedomain.

Moreover, the present invention fills this need by providing novelsoluble cytokine receptors that can be used to antagonize the effects ofT-cell inducible factor (IL-TIF) in certain human disease states. Inparticular, the present invention provides for an extracellularligand-binding region of a mammalian Zcytor11 receptor, that is eitherhomodimeric, heterodimeric, or multimeric.

Within one aspect, the present invention provides an isolatedpolynucleotide that encodes a soluble cytokine receptor polypeptidecomprising a sequence of amino acid residues that is at least 90%identical to the amino acid sequence as shown in SEQ ID NO:3, andwherein the soluble cytokine receptor polypeptide encoded by thepolynucleotide sequence binds or antagonizes IL-TIF (SEQ ID NO:8). Inone embodiment, the polynucleotide is as disclosed above, wherein thesoluble cytokine receptor polypeptide encoded by the polynucleotideforms a homodimeric receptor complex.

Within a second aspect, the present invention provides an isolatedpolynucleotide that encodes a soluble cytokine receptor polypeptidecomprising a sequence of amino acid residues that is at least 90%identical to the amino acid sequence as shown in SEQ ID NO:3, whereinthe soluble cytokine receptor polypeptide encoded by the polynucleotideforms a heterodimeric or multimeric receptor complex. In one embodiment,the polynucleotide is as disclosed above, wherein the soluble cytokinereceptor polypeptide encoded by the polynucleotide forms a heterodimericor multimeric receptor complex further comprising a soluble Class I orClass II cytokine receptor. In another embodiment, the polynucleotide isas disclosed above, wherein the soluble cytokine receptor polypeptideencoded by the polynucleotide forms a heterodimeric or multimericreceptor complex further comprising a soluble CRF2-4 receptorpolypeptide (SEQ ID NO:33) or a soluble IL-10 receptor polypeptide (SEQID NO:34), or a soluble DIRS1 receptor polypeptide (SEQ ID NO:35). Inanother embodiment, the polynucleotide is as disclosed above, whereinthe soluble cytokine receptor polypeptide encoded by the polynucleotideforms a heterodimeric or multimeric receptor complex further comprisinga soluble CRF2-4 receptor polypeptide (SEQ ID NO:33) or a soluble IL-10receptor polypeptide (SEQ ID NO:34), or a soluble DIRS1 receptorpolypeptide (SEQ ID NO:35).

Within a third aspect, the present invention provides an isolatedpolynucleotide that encodes a soluble cytokine receptor polypeptidecomprising a sequence of amino acid residues as shown in SEQ ID NO:3,wherein the soluble cytokine receptor polypeptide encoded by thepolynucleotide forms a heterodimeric or multimeric receptor complex. Inanother embodiment, the polynucleotide is as disclosed above, whereinthe soluble cytokine receptor polypeptide encoded by the polynucleotidefurther comprises a soluble Class I or Class II cytokine receptor. Inanother embodiment, the polynucleotide is as disclosed above, whereinthe soluble cytokine receptor polypeptide encoded by the polynucleotideforms a heterodimeric or multimeric receptor complex further comprisinga soluble CRF2-4 receptor polypeptide (SEQ ID NO:33) or a soluble IL-10receptor polypeptide (SEQ ID NO:34), or a soluble DIRS1 receptorpolypeptide (SEQ ID NO:35). In another embodiment, the polynucleotide isas disclosed above, wherein the soluble cytokine receptor polypeptidefurther encodes an intracellular domain. In another embodiment, thepolynucleotide is as disclosed above, wherein the soluble cytokinereceptor polypeptide further comprises an affinity tag.

Within another aspect, the present invention provides an expressionvector comprising the following operably linked elements: (a) atranscription promoter; a first DNA segment encoding a soluble cytokinereceptor polypeptide having an amino acid sequence as shown in SEQ IDNO:3; and a transcription terminator; and (b) a second transcriptionpromoter; a second DNA segment encoding a soluble Class I or Class IIcytokine receptor polypeptide; and a transcription terminator; andwherein the first and second DNA segments are contained within a singleexpression vector or are contained within independent expressionvectors.

In one embodiment, the expression vector disclosed above, furthercomprises a secretory signal sequence operably linked to the first andsecond DNA segments. In another embodiment, the expression vector is asdisclosed above, wherein the second DNA segment encodes a soluble CRF2-4receptor polypeptide (SEQ ID NO:33) or a soluble L-10 receptorpolypeptide (SEQ ID NO:34), or a soluble DIRS1 receptor polypeptide (SEQID NO:35).

Within another aspect, the present invention provides a cultured cellcomprising an expression vector as disclosed above, wherein the cellexpresses the polypeptides encoded by the DNA segments. In oneembodiment, the cultured cell comprises an expression vector asdisclosed above, wherein the first and second DNA segments are locatedon independent expression vectors and are co-transfected into the cell,and cell expresses the polypeptides encoded by the DNA segments. Inanother embodiment, the cultured cell comprises an expression vector asdisclosed above, wherein the cell expresses a heterodimeric ormultimeric soluble receptor polypeptide encoded by the DNA segments. Inanother embodiment, the cultured cell is as disclosed above, wherein thecell secretes a soluble cytokine receptor polypeptide heterodimer ormultimeric complex. In another embodiment, the cultured cell is asdisclosed above, wherein the cell secretes a soluble cytokine receptorpolypeptide heterodimer or multimeric complex that binds IL-TIF orantagonizes IL-TIF activity.

Within another aspect, the present invention provides a DNA constructencoding a fusion protein comprising: a first DNA segment encoding apolypeptide having a sequence of amino acid residues as shown in SEQ IDNO:3; and at least one other DNA segment encoding a soluble Class I orClass II cytokine receptor polypeptide, wherein the first and other DNAsegments are connected in-frame; and wherein the first and other DNAsegments encode the fusion protein.

Within another aspect, the present invention provides a DNA constructencoding a fusion protein as disclosed above, wherein at least one otherDNA segment encodes a soluble CRF2-4 receptor polypeptide (SEQ ID NO:33)or a soluble IL-10 receptor polypeptide (SEQ ID NO:34), or a solubleDIRS1 receptor polypeptide (SEQ ID NO:35).

Within another aspect, the present invention provides an expressionvector comprising the following operably linked elements: atranscription promoter; a DNA construct encoding a fusion protein asdisclosed above; and

a transcription terminator, wherein the promoter is operably linked tothe DNA construct, and the DNA construct is operably linked to thetranscription terminator.

Within another aspect, the present invention provides a cultured cellcomprising an expression vector as disclosed above, wherein the cellexpresses a polypeptide encoded by the DNA construct.

Within another aspect, the present invention provides a method ofproducing a fusion protein comprising: culturing a cell as disclosedabove; and isolating the polypeptide produced by the cell.

Within another aspect, the present invention provides an isolatedsoluble cytokine receptor polypeptide comprising a sequence of aminoacid residues that is at least 90% identical to an amino acid sequenceas shown in SEQ ID NO:3, and wherein the soluble cytokine receptorpolypeptide binds IL-TIF or antagonizes IL-TIF activity. In oneembodiment, the isolated polypeptide is as disclosed above, wherein thesoluble cytokine receptor polypeptide forms a homodimeric receptorcomplex.

Within another aspect, the present invention provides an isolatedpolypeptide comprising a sequence of amino acid residues that is atleast 90% identical to an amino acid sequence as shown in SEQ ID NO:3,wherein the soluble cytokine receptor polypeptide forms a heterodimericor multimeric receptor complex. In one embodiment, the isolatedpolypeptide is as disclosed above, wherein the soluble cytokine receptorpolypeptide forms a heterodimeric or multimeric receptor complex furthercomprising a soluble Class I or Class II cytokine receptor.

In another embodiment, the isolated polypeptide is as disclosed above,wherein the soluble cytokine receptor polypeptide forms a heterodimericor multimeric receptor complex further comprising a soluble CRF2-4receptor polypeptide (SEQ ID NO:33) or a soluble IL-10 receptorpolypeptide (SEQ ID NO:34), or a soluble DIRS1 receptor polypeptide (SEQID NO:35). In another embodiment, the isolated polypeptide is asdisclosed above, wherein the polypeptide forms a heterodimeric ormultimeric receptor complex further comprising a soluble CRF2-4 receptorpolypeptide (SEQ ID NO:33) or a soluble IL-10 receptor polypeptide (SEQID NO:34), or a soluble DIRS1 receptor polypeptide (SEQ ID NO:35).

Within another aspect, the present invention provides an isolatedsoluble cytokine receptor polypeptide comprising a sequence of aminoacid residues as shown in SEQ ID NO:3, wherein the soluble cytokinereceptor polypeptide forms a heterodimeric or multimeric receptorcomplex. In another embodiment, the isolated polypeptide is as disclosedabove, wherein the soluble cytokine receptor polypeptide forms aheterodimeric or multimeric receptor complex further comprising asoluble Class I or Class II cytokine receptor. In another embodiment,the isolated polypeptide is as disclosed above, wherein the solublecytokine receptor polypeptide forms a heterodimeric or multimericreceptor complex comprising a soluble CRF2-4 receptor polypeptide (SEQID NO:33) or a soluble IL-10 receptor polypeptide (SEQ ID NO:34), or asoluble DIRS1 receptor polypeptide (SEQ ID NO:35). In anotherembodiment, the isolated polypeptide is as disclosed above, wherein thesoluble cytokine receptor polypeptide further comprises an affinity tag,chemical moiety, toxin, or label. Within another aspect, the presentinvention provides an isolated heterodimeric or multimeric solublereceptor complex comprising soluble receptor subunits, wherein at leastone of soluble receptor subunits comprises a soluble cytokine receptorpolypeptide comprising a sequence of amino acid residues as shown in SEQID NO:3. In one embodiment, the isolated heterodimeric or multimericsoluble receptor complex disclosed above, further comprises a solubleClass I or Class II cytokine receptor polypeptide. In one embodiment,the isolated heterodimeric or multimeric soluble receptor complexdisclosed above, further comprises a soluble CRF2-4 receptor polypeptide(SEQ ID NO:33) or a soluble IL-10 receptor polypeptide (SEQ ID NO:34),or a soluble DIRS1 receptor polypeptide (SEQ ID NO:35).

Within another aspect, the present invention provides a method ofproducing a soluble cytokine receptor polypeptide that forms aheterodimeric or multimeric complex comprising: culturing a cell asdisclosed above; and isolating the soluble receptor polypeptidesproduced by the cell.

Within another aspect, the present invention provides a method ofproducing an antibody to soluble cytokine receptor polypeptidecomprising: inoculating an animal with a soluble cytokine receptorpolypeptide selected from the group consisting of: (a) a polypeptidecomprising a homodimeric soluble cytokine receptor complex; (b) apolypeptide comprising a soluble cytokine receptor heterodimeric ormultimeric receptor complex comprising a soluble Class I or Class IIcytokine receptor polypeptide; (c) a polypeptide comprising a solublecytokine receptor heterodimeric or multimeric receptor complexcomprising a soluble CRF2-4 receptor polypeptide (SEQ ID NO:33); (d) apolypeptide comprising a soluble cytokine receptor heterodimeric ormultimeric receptor complex comprising a soluble IL-10 receptorpolypeptide (SEQ ID NO:34); (e) a polypeptide comprising a solublecytokine receptor heterodimeric or multimeric receptor complexcomprising a soluble DIRS1 receptor polypeptide (SEQ ID NO:34); andwherein the polypeptide elicits an immune response in the animal toproduce the antibody; and isolating the antibody from the animal.

Within another aspect, the present invention provides an antibodyproduced by the method as disclosed above, which specifically binds to ahomodimeric, heterodimeric or multimeric receptor complex comprising asoluble cytokine receptor polypeptide. In one embodiment, the antibodydisclosed above is a monoclonal antibody.

Within another aspect, the present invention provides an antibody whichspecifically binds to a homodimeric, heterodimeric or multimericreceptor complex as disclosed above.

Within another aspect, the present invention provides a method forinhibiting IL-TIF-induced proliferation of hematopoietic cells andhematopoietic cell progenitors comprising culturing bone marrow orperipheral blood cells with a composition comprising an amount ofsoluble cytokine receptor sufficient to reduce proliferation of thehematopoietic cells in the bone marrow or peripheral blood cells ascompared to bone marrow or peripheral blood cells cultured in theabsence of soluble cytokine receptor. In one embodiment, the method isas disclosed above, wherein the hematopoietic cells and hematopoieticprogenitor cells are lymphoid cells. In one embodiment, the method is asdisclosed above, wherein the lymphoid cells are macrophages or T cells.

Within another aspect, the present invention provides a method ofreducing IL-TIF-induced or IL-9 induced inflammation comprisingadministering to a mammal with inflammation an amount of a compositionof soluble cytokine receptor sufficient to reduce inflammation.

Within another aspect, the present invention provides a method ofsuppressing an immune response in a mammal exposed to an antigen orpathogen comprising: (1) determining a level of an antigen- orpathogen-specific antibody; (2) administering a composition comprisingsoluble cytokine receptor polypeptide in an acceptable pharmaceuticalvehicle; (3) determining a post administration level of antigen- orpathogen-specific antibody; (4) comparing the level of antibody in step(1) to the level of antibody in step (3), wherein a lack of increase ora decrease in antibody level is indicative of suppressing an immuneresponse.

These and other aspects of the invention will become evident uponreference to the following detailed description and the attacheddrawing.

The term “allelic variant” is used herein to denote any of two or morealternative forms of a gene occupying the same chromosomal locus.Allelic variation arises naturally through mutation, and may result inphenotypic polymorphism within populations. Gene mutations can be silent(no change in the encoded polypeptide) or may encode polypeptides havingaltered amino acid sequence. The term allelic variant is also usedherein to denote a protein encoded by an allelic variant of a gene.

“Corresponding to”, when used in reference to a nucleotide or amino acidsequence, indicates the position in a second sequence that aligns withthe reference position when two sequences are optimally aligned.

The term “expression vector” is used to denote a DNA molecule, linear orcircular, that comprises a segment encoding a polypeptide of interestoperably linked to additional segments that provide for itstranscription. Such additional segments include promoter and terminatorsequences, and may also include one or more origins of replication, oneor more selectable markers, an enhancer, a polyadenylation signal, etc.Expression vectors are generally derived from plasmid or viral DNA, ormay contain elements of both.

The term “isolated”, when applied to a polynucleotide, denotes that thepolynucleotide has been removed from its natural genetic milieu and isthus free of other extraneous or unwanted coding sequences, and is in aform suitable for use within genetically engineered protein productionsystems.

“Operably linked”, when referring to DNA segments, indicates that thesegments are arranged so that they function in concert for theirintended purposes, e.g. transcription initiates in the promoter andproceeds through the coding segment to the terminator.

A “polynucleotide” is a single- or double-stranded polymer ofdeoxyribonucleotide or ribonucleotide bases read from the 5′ to the 3′end. Polynucleotides include RNA and DNA, and may be isolated fromnatural sources, synthesized in vitro, or prepared from a combination ofnatural and synthetic molecules.

The term “promoter” is used herein for its art-recognized meaning todenote a portion of a gene containing DNA sequences that provide for thebinding of RNA polymerase and initiation of transcription. Promotersequences are commonly, but not always, found in the 5′ non-codingregions of genes.

The term “receptor” is used herein to denote a cell-associated protein,or a polypeptide subunit of such a protein, that binds to a bioactivemolecule (the “ligand”) and mediates the effect of the ligand on thecell. Binding of ligand to receptor results in a conformational changein the receptor (and, in some cases, receptor multimerization, i.e.,association of identical or different receptor subunits) that causesinteractions between the effector domain(s) and other molecule(s) in thecell. These interactions in turn lead to alterations in the metabolismof the cell. Metabolic events that are linked to receptor-ligandinteractions include gene transcription, phosphorylation,dephosphorylation, cell proliferation, increases in cyclic AMPproduction, mobilization of cellular calcium, mobilization of membranelipids, cell adhesion, hydrolysis of inositol lipids and hydrolysis ofphospholipids. The term “receptor polypeptide” is used to denotecomplete receptor polypeptide chains and portions thereof, includingisolated functional domains (e.g., ligand-binding domains).

A “secretory signal sequence” is a DNA sequence that encodes apolypeptide (a “secretory peptide”) that, as a component of a largerpolypeptide, directs the larger polypeptide through a secretory pathwayof a cell in which it is synthesized.

The larger polypeptide is commonly cleaved to remove the secretorypeptide during transit through the secretory pathway.

A “soluble receptor” is a receptor polypeptide that is not bound to acell membrane. Soluble receptors are most commonly ligand-bindingreceptor polypeptides that lack transmembrane and cytoplasmic domains.Soluble receptors can comprise additional amino acid residues, such asaffinity tags that provide for purification of the polypeptide orprovide sites for attachment of the polypeptide to a substrate, orimmunoglobulin constant region sequences. Many cell-surface receptorshave naturally occurring, soluble counterparts that are produced byproteolysis or translated from alternatively spliced mRNAs. Receptorpolypeptides are said to be substantially free of transmembrane andintracellular polypeptide segments when they lack sufficient portions ofthese segments to provide membrane anchoring or signal transduction,respectively.

The term “splice variant” is used herein to denote alternative forms ofRNA transcribed from a gene. Splice variation arises naturally throughuse of alternative splicing sites within a transcribed RNA molecule, orless commonly between separately transcribed RNA molecules, and mayresult in several mRNAs transcribed from the same gene. Splice variantsmay encode polypeptides having altered amino acid sequence. The termsplice variant is also used herein to denote a protein encoded by asplice variant of an mRNA transcribed from a gene.

Molecular weights and lengths of polymers determined by impreciseanalytical methods (e.g., gel electrophoresis) will be understood to beapproximate values. When such a value is expressed as “about” X or“approximately” X, the stated value of X will be understood to beaccurate to ±10%.

Cytokine receptors subunits are characterized by a multi-domainstructure comprising a ligand-binding domain and an effector domain thatis typically involved in signal transduction. Multimeric cytokinereceptors include homodimers (e.g., PDGF receptor αα and ββ isoforms,erythropoietin receptor, MPL (thrombopoietin receptor), and G-CSFreceptor), heterodimers whose subunits each have ligand-binding andeffector domains (e.g., PDGF receptor αβ isoform), and multimers havingcomponent subunits with disparate functions (e.g., IL-2, IL-3, IL-4,IL-5, IL-6, IL-7, and GM-CSF receptors). Some receptor subunits arecommon to a plurality of receptors. For example, the AIC2B subunit,which cannot bind ligand on its own but includes an intracellular signaltransduction domain, is a component of IL-3 and GM-CSF receptors. Manycytokine receptors can be placed into one of four related families onthe basis of their structures and functions. Class I hematopoieticreceptors, for example, are characterized by the presence of a domaincontaining conserved cysteine residues and the WSXWS motif. Additionaldomains, including protein kinase domains; fibronectin type III domains;and immunoglobulin domains, which are characterized by disulfide-bondedloops, are present in certain hematopoietic receptors. Cytokine receptorstructure has been reviewed by Urdal, Ann. Reports Med. Chem.26:221–228, 1991 and Cosman, Cytokine 5:95–106, 1993. It is generallybelieved that under selective pressure for organisms to acquire newbiological functions, new receptor family members arose from duplicationof existing receptor genes leading to the existence of multi-genefamilies. Family members thus contain vestiges of the ancestral gene,and these characteristic features can be exploited in the isolation andidentification of additional family members.

Cell-surface cytokine receptors are further characterized by thepresence of additional domains. These receptors are anchored in the cellmembrane by a transmembrane domain characterized by a sequence ofhydrophobic amino acid residues (typically about 21–25 residues), whichis commonly flanked by positively charged residues (Lys or Arg). On theopposite end of the protein from the extracellular domain and separatedfrom it by the transmembrane domain is an intracellular domain.

The Zcytor11 receptor is a class II cytokine receptor. These receptorsusually bind to four-helix-bundle cytokines. Interleukin-10 and theinterferons have receptors in this class (e.g., interferon-gamma alphaand beta chains and the interferon-alpha/beta receptor alpha and betachains). Class II cytokine receptors are characterized by the presenceof one or more cytokine receptor modules (CRM) in their extracellulardomains. The CRMs of class II cytokine receptors are somewhat differentthan the better known CRMs of class I cytokine receptors. While theclass II CRMs contain two type-III fibronectin-like domains, they differin organization.

Zcytor11, like all known class II receptors except interferon-alpha/betareceptor alpha chain, has only a single class II CRM in itsextracellular domain. Zcytor11 is a receptor for a helical cytokine ofthe interferon/IL-10 class. As was stated above, Zcytor11 is similar tothe interferon α receptor α chain. Uze et al. Cell 60 255–264 (1996)Analysis of a human cDNA clone encoding Zcytor11 (SEQ ID NO:1) revealedan open reading frame encoding 574 amino acids (SEQ ID NO:2) comprisingan extracellular ligand-binding domain of approximately 211 amino acidresidues (residues 18–228 of SEQ ID NO:2; SEQ ID NO:3), a transmembranedomain of approximately 23 amino acid residues (residues 229–251 of SEQID NO:2), and an intracellular domain of approximately 313 amino acidresidues (residues 252 to 574 of SEQ ID NO:2). Those skilled in the artwill recognize that these domain boundaries are approximate and arebased on alignments with known proteins and predictions of proteinfolding. Deletion of residues from the ends of the domains is possible.

Moreover, the zcytor11 receptor has been shown to bind a ligand calledT-cell inducible Factor (TIF, or IL-TIF) (See, WIPO publication WO00/24758; Dumontier et al., J. Immunol. 164:1814–1819, 2000; and Xie etal., J. Biol. Chem. manuscript in press M005304200). The human IL-TIFnucleotide sequence is represented in SEQ ID NO:7 and correspondingpolypeptide sequence is shown in SEQ ID NO:8. Within preferredembodiments, the soluble receptor form of zcytor11, residues 18–228 ofSEQ ID NO:2, (SEQ ID NO:3) is a homodimer, heterodimer, or multimer thatantagonizes the effects of IL-TIF in vivo. Antibodies to such homodimer,heterodimer, or multimers also serve as antagonists of IL-TIF activity.

IL-TIF has been shown to be induced in the presence of IL-9, and issuspected to be involved in promoting Th1-type immune responses. IL-9stimulates proliferation, activation, differentiation and/or inductionof immune function in a variety of ways and is implicated in asthma,lung mastocytosis, and other diseases, as well as activate STATpathways. Antagonists of IL-TIF or IL-9 function can have beneficial useagainst such human diseases. The present invention provides such novelantagonists of IL-TIF.

The present invention is based in part upon the discovery of a novelheterodimeric soluble receptor protein having the structure of a classII cytokine receptor, and antibodies thereto. The heterodimeric solublereceptor includes at least one zcytor11 soluble receptor subunit,disclosed in the commonly owned U.S. Pat. No. 5,965,704. A secondsoluble receptor polypeptide included in the heterodimeric solublereceptor belongs to the receptor subfamily that includes Interleukin-10(Liu Y et al, J. Immunol. 152; 1821–1829, 1994 (IL-10R cDNA) (SEQ IDNO:34)), the interferons (e.g., interferon-gamma alpha and beta chainsand the interferon-alpha/beta receptor alpha and beta chains), CRF2-4(Genbank Accession No. Z17227; SEQ ID NO:33), and DIRS1 (WIPOPublication WO99/46379, Schering Corporation, 1999; SEQ ID NO:35). Thezcytor11 receptor in conjunction with CRF2-4 and IL-10 Receptor wasshown to signal JAK-STAT pathway in response to the natural ligand forthe zcytor11 receptor, IL-TIF (Xie et al., supra.). According to thepresent invention, a heterodimeric soluble zcytor11 receptor, asexemplified by a preferred embodiment of a soluble zcytor11receptor+soluble CRF2-4 receptor heterodimer (zcytor11/CRF2-4), can actas a potent antagonist of the IL-TIF. Other embodiments include solubleheterodimer zcytor11/IL-10R, zcytor11/IL-9R, and other class II receptorsubunits, as well as multimeric receptors including but not limited tozcytor11/CRF2-4/IL-10R, and zcytor11/CRF2-4/IL-9R.

Analysis of the tissue distribution of the mRNA corresponding zcytor11cDNA showed that mRNA level was highest in pancreas, followed by a muchlower levels in thymus, colon, liver, skin, lung, kidney and smallintestine. Thus, particular embodiments of the present invention aredirected toward use of soluble zcytor11 heterodimers as antagonists ininflammatory and immune diseases or conditions such as pancreatitis,type I diabetes (IDDM), pancreatic cancer, pancreatitis, Graves Disease,inflammatory bowel disease (IBD), Crohn's Disease, colon and intestinalcancer, diverticulosis, autoimmune disease, sepsis, asthma, end-stagerenal diseases, psoriasis, organ or bone marrow transplant; and whereinhibition of inflammation, immune suppression, reduction ofproliferation of hematopoietic, immune, inflammatory or lymphoid cells,macrophages, T-cells (including Th1 and Th2 cells), suppression ofimmune response to a pathogen or antigen, or inhibition of IL-TIF orIL-9 cytokine production is desired.

Moreover, antibodies recognizing zcytoR11, soluble zcytoR11/CRF2-4heterodimers, and multimers described herein and/or solublezcytoR11/CRF2-4 heterodimers, and multimers themselves are useful to:

1) Antagonize or block signaling via the IL-TIF receptors in thetreatment of autoimmune diseases such as IDDM, multiple sclerosis (MS),systemic Lupus erythematosus (SLE), myasthenia gravis, rheumatoidarthritis, and IBD to prevent or inhibit signaling in immune cells (e.g.lymphocytes, monocytes, leukocytes) via zcytoR11 (Hughes C et al., J.Immunol 153: 3319–3325, 1994). Alternatively anti-soluble zcytor11,anti-soluble zcytoR11/CRF2-4 heterodimer or mulitmer monoclonal antibody(Mab) can be used as an antagonist to deplete unwanted immune cells totreat autoimmune disease. Asthma, allergy and other atopic disease maybe treated with an MAb against soluble zcytor11 soluble zcytoR11/CRF2-4heterodimers to inhibit the immune response or to deplete offendingcells. Blocking or inhibiting signaling via zcytoR11, using thepolypeptides and antibodies of the present invention, may also benefitdiseases of the pancreas, kidney, pituitary and neuronal cells. IDDM,NIDDM, pancreatitis, and pancreatic carcinoma may benefit. ZcytoR11 mayserve as a target for MAb therapy of cancer where an antagonizing MAbinhibits cancer growth and targets immune-mediated killing. (Holliger P,and Hoogenboom, H: Nature Biotech. 16: 1015–1016, 1998). Mabs to solublezcytoR11, and soluble zcytoR11/CRF2-4 heterodimers and multimers mayalso be useful to treat nephropathies such as glomerulosclerosis,membranous neuropathy, amyloidosis (which also affects the kidney amongother tissues), renal arteriosclerosis, glomerulonephritis of variousorigins, fibroproliferative diseases of the kidney, as well as kidneydysfunction associated with SLE, IDDM, type II diabetes (NIDDM), renaltumors and other diseases.

2) Agonize or initiate signaling via the IL-TIF receptors in thetreatment of autoimmune diseases such as IDDM, MS, SLE, myastheniagravis, rheumatoid arthritis, and IBD. Anti-soluble zcytor11,anti-soluble zcytoR11/CRF2-4 heterodimers and multimer monoclonalantibodies may signal lymphocytes or other immune cells todifferentiate, alter proliferation, or change production of cytokines orcell surface proteins that ameliorate autoimmunity. Specifically,modulation of a T-helper cell response to an alternate pattern ofcytokine secretion may deviate an autoimmune response to amelioratedisease (Smith JA et al., J. Immunol. 160:4841–4849, 1998). Similarly,agonistic Anti-soluble zcytor11, anti-solublezcytoR11/CRF2-4heterodimers and multimer monoclonal antibodies may be used to signal,deplete and deviate immune cells involved in asthma, allergy and atopoicdisease. Signaling via zcytoR11 may also benefit diseases of thepancreas, kidney, pituitary and neuronal cells. IDDM, NIDDM,pancreatitis, and pancreatic carcinoma may benefit. ZcytoR11 may serveas a target for MAb therapy of pancreatic cancer where a signaling MAbinhibits cancer growth and targets immune-mediated killing (Tutt, A L etal., J Immunol. 161: 3175–3185, 1998). Similarly renal cell carcinomamay be treated with monoclonal antibodies to zcytor11-comprising solublereceptors of the present invention.

Soluble zcytor11, soluble zcytoR11/CRF2-4 heterodimers and multimersdescribed herein can be used to neutralize/block IL-TIF activity in thetreatment of autoimmune disease, atopic disease, NIDDM, pancreatitis andkidney dysfunction as described above. A soluble form of zcytoR11 may beused to promote an antibody response mediated by Th cells and/or topromote the production of IL-4 or other cytokines by lymphocytes orother immune cells.

The soluble receptors of the present invention are useful as antagonistsof the IL-TIF cytokine. Such antagonistic effects can be achieved bydirect neutralization or binding of the IL-TIF. In addition toantagonistic uses, the soluble receptors of the present invention canbind IL-TIF and act as carrier proteins for the IL-TIF cytokine, inorder to transport the Ligand to different tissues, organs, and cellswithin the body. As such, the soluble receptors of the present inventioncan be fused or coupled to molecules, polypeptides or chemical moietiesthat direct the soluble-receptor-Ligand complex to a specific site, suchas a tissue, specific immune cell, or tumor. Thus, the soluble receptorsof the present invention can be used to specifically direct the actionof the IL-TIF. See, Cosman, D. Cytokine 5: 95–106, 1993; andFernandez-Botran, R. Exp. Opin. Invest. Drugs 9:497–513, 2000.

Moreover, the soluble receptors of the present invention can be used tostabilize the IL-TIF, to increase the bio-availability, therapeuticlongevity, and/or efficacy of the Ligand by stabilizing the Ligand fromdegradation or clearance, or by targeting the ligand to a site of actionwithin the body. For example the naturally occurring IL-6/soluble IL-6Rcomplex stabilizes IL-6 and can signal through the gp130 receptor. See,Cosman, D. supra., and Femandez-Botran, R. supra.

Within preferred embodiments of the invention the isolatedpolynucleotides will hybridize to similar sized regions of nucleotidesSEQ ID NO:1 corresponding to SEQ ID NO:3 or a sequence complementarythereto, under stringent conditions. In general, stringent conditionsare selected to be about 5° C. lower than the thermal melting point(T_(m)) for the specific sequence at a defined ionic strength and pH.The T_(m) is the temperature (under defined ionic strength and pH) atwhich 50% of the target sequence hybridizes to a perfectly matchedprobe. Typical stringent conditions are those in which the saltconcentration is at least about 0.02 M at pH 7 and the temperature is atleast about 60° C. As previously noted, the isolated polynucleotides ofthe present invention include DNA and RNA. Methods for isolating DNA andRNA are well known in the art. It is generally preferred to isolate RNAfrom pancreas or prostate tissues although cDNA can also be preparedusing RNA from other tissues or isolated as genomic DNA. Total RNA canbe prepared using guanidine HCl extraction followed by isolation bycentrifugation in a CsCl gradient (Chirgwin et al., Biochemistry18:52–94, (1979)). Poly (A)⁺ RNA is prepared from total RNA using themethod of Aviv and Leder Proc. Natl. Acad. Sci. USA 69:1408–1412,(1972). Complementary DNA (cDNA) is prepared from poly(A)⁺ RNA usingknown methods. Polynucleotides encoding Zcytor11 polypeptides are thenidentified and isolated by, for example, hybridization or PCR.

Those skilled in the art will recognize that the sequences disclosed inSEQ ID NO:3 and the corresponding nucleotides of SEQ ID NO:1 andrepresent single alleles of the human Zcytor11 receptor. Allelicvariants of these sequences can be cloned by probing cDNA or genomiclibraries from different individuals according to standard procedures.

The present invention further provides counterpart receptors andpolynucleotides from other species (“species orthologs”). Of particularinterest are Zcytor11 receptors from other mammalian species, includingmurine, porcine, ovine, bovine, canine, feline, equine, and non-humanprimates. Species orthologs of the human Zcytor11 receptor can be clonedusing information and compositions provided by the present invention incombination with conventional cloning techniques. For example, a cDNAcan be cloned using mRNA obtained from a tissue or cell type thatexpresses the receptor. Suitable sources of mRNA can be identified byprobing Northern blots with probes designed from the sequences disclosedherein. A library is then prepared from mRNA of a positive tissue orcell line. A receptor-encoding cDNA can then be isolated by a variety ofmethods, such as by probing with a complete or partial cDNA of human andother primates or with one or more sets of degenerate probes based onthe disclosed sequences. A cDNA can also be cloned using the polymerasechain reaction, or PCR (Mullis, U.S. Pat. No. 4,683,202), using primersdesigned from the sequences disclosed herein. Within an additionalmethod, the cDNA library can be used to transform or transfect hostcells, and expression of the cDNA of interest can be detected with anantibody to the receptor. Similar techniques can also be applied to theisolation of genomic clones.

The present invention also provides isolated soluble monomeric,homodimeric, heterodimeric and multimeric receptor polypeptides thatcomprise at least one zcytor11 receptor subunit that is substantiallyhomologous to the receptor polypeptide of SEQ ID NO:3. By “isolated” ismeant a protein or polypeptide that is found in a condition other thanits native environment, such as apart from blood and animal tissue. In apreferred form, the isolated polypeptide is substantially free of otherpolypeptides, particularly other polypeptides of animal origin. It ispreferred to provide the polypeptides in a highly purified form, i.e.greater than 95% pure, more preferably greater than 99% pure. The term“substantially homologous” is used herein to denote polypeptides having50%, preferably 60%, more preferably at least 80%, sequence identity tothe sequences shown in SEQ ID NO:3. Such polypeptides will morepreferably be at least 90% identical, and most preferably 95% or moreidentical to SEQ ID NO:3. Percent sequence identity is determined byconventional methods. See, for example, Altschul et al., Bull. Math.Bio. 48: 603–616, (1986) and Henikoff and Henikoff, Proc. Natl. Acad.Sci. USA 89:10915–10919, (1992). Briefly, two amino acid sequences arealigned to optimize the alignment scores using a gap opening penalty of10, a gap extension penalty of 1, and the “blossom 62” scoring matrix ofHenikoff and Henikoff (id.) as shown in Table 2 (amino acids areindicated by the standard one-letter codes). The percent identity isthen calculated as:

$\frac{{Total}\mspace{14mu}{number}\mspace{14mu}{of}\mspace{14mu}{identical}\mspace{14mu}{matches}}{\begin{matrix}\left\lbrack {{length}\mspace{14mu}{of}\mspace{14mu}{the}\mspace{14mu} l\;{onger}\mspace{14mu}{sequence}\mspace{14mu}{plus}\mspace{14mu}{the}}\mspace{14mu} \right. \\{{number}\mspace{14mu}{of}\mspace{14mu}{gaps}\mspace{14mu}{introduced}\mspace{14mu}{into}\mspace{14mu}{the}\mspace{14mu}{longer}} \\\left. {{sequence}\mspace{14mu}{in}\mspace{14mu}{order}\mspace{14mu}{to}\mspace{11mu}{align}\mspace{14mu}{the}\mspace{14mu}{two}\mspace{14mu}{sequences}} \right\rbrack\end{matrix}} \times 100$

TABLE 2 A R N D C Q E G H I L K M F P S T W Y V A 4 R −1 5 N −2 0 6 D −2−2 1 6 C 0 −3 −3 −3 9 Q −1 1 0 0 −3 5 E −1 0 0 2 −4 2 5 G 0 −2 0 −1 −3−2 −2 6 H −2 0 1 −1 −3 0 0 −2 8 I −1 −3 −3 −3 −1 −3 −3 −4 −3 4 L −1 −2−3 −4 −1 −2 −3 −4 −3 2 4 K −1 2 0 −1 −3 1 1 −2 −1 −3 −2 5 M −1 −1 −2 −3−1 0 −2 −3 −2 1 2 −1 5 F −2 −3 −3 −3 −2 −3 −3 −3 −1 0 0 −3 0 6 P −1 −2−2 −1 −3 −1 −1 −2 −2 −3 −3 −1 −2 −4 7 S 1 −1 1 0 −1 0 0 0 −1 −2 −2 0 −1−2 −1 4 T 0 −1 0 −1 −1 −1 −1 −2 −2 −1 −1 −1 −1 −2 −1 1 5 W −3 −3 −4 −4−2 −2 −3 −2 −2 −3 −2 −3 −1 1 −4 −3 −2 11 Y −2 −2 −2 −3 −2 −1 −2 −3 2 −1−1 −2 −1 3 −3 −2 −2 2 7 V 0 −3 −3 −3 −1 −2 −2 −3 −3 3 1 −2 1 −1 −2 −2 0−3 −1 4

Sequence identity of polynucleotide molecules is determined by similarmethods using a ratio as disclosed above.

Those skilled in the art appreciate that there are many establishedalgorithms available to align two amino acid sequences. The “FASTA”similarity search algorithm of Pearson and Lipman is a suitable proteinalignment method for examining the level of identity shared by an aminoacid sequence disclosed herein and the amino acid sequence of a putativevariant ztryp1. The FASTA algorithm is described by Pearson and Lipman,Proc. Nat'l Acad. Sci. USA 85:2444 (1988), and by Pearson, Meth.Enzymol. 183:63 (1990).

Briefly, FASTA first characterizes sequence similarity by identifyingregions shared by the query sequence (e.g., SEQ ID NO:3) and a testsequence that have either the highest density of identities (if the ktupvariable is 1) or pairs of identities (if ktup=2), without consideringconservative amino acid substitutions, insertions, or deletions. The tenregions with the highest density of identities are then rescored bycomparing the similarity of all paired amino acids using an amino acidsubstitution matrix, and the ends of the regions are “trimmed” toinclude only those residues that contribute to the highest score. Ifthere are several regions with scores greater than the “cutoff” value(calculated by a predetermined formula based upon the length of thesequence and the ktup value), then the trimmed initial regions areexamined to determine whether the regions can be joined to form anapproximate alignment with gaps. Finally, the highest scoring regions ofthe two amino acid sequences are aligned using a modification of theNeedleman-Wunsch-Sellers algorithm (Needleman and Wunsch, J. Mol. Biol.48:444 (1970); Sellers, SIAM J. Appl. Math. 26:787 (1974)), which allowsfor amino acid insertions and deletions. Preferred parameters for FASTAanalysis are: ktup=1, gap opening penalty=10, gap extension penalty=1,and substitution matrix=BLOSUM62. These parameters can be introducedinto a FASTA program by modifying the scoring matrix file (“SMATRIX”),as explained in Appendix 2 of Pearson, Meth. Enzymol., supra.

FASTA can also be used to determine the sequence identity of nucleicacid molecules using a ratio as disclosed above. For nucleotide sequencecomparisons, the ktup value can range between one to six, preferablyfrom three to six, most preferably three, with other FASTA programparameters set as default.

The BLOSUM62 table (Table 2) is an amino acid substitution matrixderived from about 2,000 local multiple alignments of protein sequencesegments, representing highly conserved regions of more than 500 groupsof related proteins (Henikoff and Henikoff, Proc. Nat'l Acad. Sci. USA89:10915 (1992)). Accordingly, the BLOSUM62 substitution frequencies canbe used to define conservative amino acid substitutions that may beintroduced into the amino acid sequences of the present invention.Although it is possible to design amino acid substitutions based solelyupon chemical properties (as discussed below), the language“conservative amino acid substitution” preferably refers to asubstitution represented by a BLOSUM62 value of greater than −1. Forexample, an amino acid substitution is conservative if the substitutionis characterized by a BLOSUM62 value of 0, 1, 2, or 3. According to thissystem, preferred conservative amino acid substitutions arecharacterized by a BLOSUM62 value of at least 1 (e.g., 1, 2 or 3), whilemore preferred conservative amino acid substitutions are characterizedby a BLOSUM62 value of at least 2 (e.g., 2 or 3).

Substantially homologous proteins and polypeptides are characterized ashaving one or more amino acid substitutions, deletions or additions.These changes are preferably of aminor nature, that is conservativeamino acid substitutions (see Table 3) and other substitutions that donot significantly affect the folding or activity of the protein orpolypeptide; small deletions, typically of one to about 30 amino acids;and small amino- or carboxyl-terminal extensions, such as anamino-terminal methionine residue, a small linker peptide of up to about20–25 residues, or a small extension that facilitates purification (anaffinity tag), such as a poly-histidine tract, protein A (Nilsson etal., EMBO J. 4:1075, (1985); Nilsson et al., Methods Enzymol. 198:3,(1991)), glutathione S transferase (Smith and Johnson, Gene 67:31,1988), or other antigenic epitope or binding domain. See, in generalFord et al., Protein Expression and Purification 2: 95–107, (1991. DNAsencoding affinity tags are available from commercial suppliers (e.g.,Pharmacia Biotech, Piscataway, N.J.).

TABLE 3 Conservative amino acid substitutions Basic: arginine lysinehistidine Acidic: glutamic acid aspartic acid Polar: glutamineasparagine Hydrophobic: leucine isoleucine valine Aromatic:phenylalanine tryptophan tyrosine Small: glycine alanine serinethreonine methionine

Essential amino acids in the receptor polypeptides of the presentinvention can be identified according to procedures known in the art,such as site-directed mutagenesis or alanine-scanning mutagenesis(Cunningham and Wells, Science 244, 1081–1085, (1989); Bass et al.,Proc. Natl. Acad. Sci. USA 88:4498–4502, (1991)). In the lattertechnique, single alanine mutations are introduced at every residue inthe molecule, and the resultant mutant molecules are tested forbiological activity (e.g., ligand binding and signal transduction) toidentify amino acid residues that are critical to the activity of themolecule. Sites of ligand-receptor interaction can also be determined byanalysis of crystal structure as determined by such techniques asnuclear magnetic resonance, crystallography or photoaffinity labeling.See, for example, de Vos et al., Science 255:306–312, (1992); Smith etal., J. Mol. Biol. 224:899–904, (1992); Wlodaver et al., FEBS Lett.309:59–64, (1992). The identities of essential amino acids can also beinferred from analysis of homologies with related receptors.

Multiple amino acid substitutions can be made and tested using knownmethods of mutagenesis and screening, such as those disclosed byReidhaar-Olson and Sauer Science 241:53–57, (1988) or Bowie and SauerProc. Natl. Acad. Sci. USA 86:2152–2156, (1989). Briefly, these authorsdisclose methods for simultaneously randomizing two or more positions ina polypeptide, selecting for functional polypeptide, and then sequencingthe mutagenized polypeptides to determine the spectrum of allowablesubstitutions at each position. Other methods that can be used includephage display e.g., Lowman et al., Biochem. 30:10832–10837, (1991);Ladner et al., U.S. Pat. No. 5,223,409; Huse, WIPO Publication WO92/06204) and region-directed mutagenesis (Derbyshire et al., Gene46:145, (1986); Ner et al., DNA 7:127, (1988)).

Mutagenesis methods as disclosed above can be combined withhigh-throughput screening methods to detect activity of cloned,mutagenized receptors in host cells. Preferred assays in this regardinclude cell proliferation assays and biosensor-based ligand-bindingassays, which are described below. Mutagenized DNA molecules that encodeactive receptors or portions thereof (e.g., ligand-binding fragments)can be recovered from the host cells and rapidly sequenced using modernequipment. These methods allow the rapid determination of the importanceof individual amino acid residues in a polypeptide of interest, and canbe applied to polypeptides of unknown structure.

Using the methods discussed above, one of ordinary skill in the art canprepare a variety of polypeptides that comprise a soluble receptorsubunit that is substantially homologous to SEQ ID NO:3 or allelicvariants thereof and retain the ligand-binding properties of thewild-type receptor. Such polypeptides may include additional amino acidsfrom an extracellular ligand-binding domain of a Zcytor11 receptor aswell as part or all of the transmembrane and intracellular domains. Suchpolypeptides may also include additional polypeptide segments asgenerally disclosed above.

The receptor polypeptides of the present invention, including solublehomodimeric, heterodimeric and multimeric receptors, full-lengthreceptors, receptor fragments (e.g. ligand-binding fragments), andfusion polypeptides can be produced in genetically engineered host cellsaccording to conventional techniques. Suitable host cells are those celltypes that can be transformed or transfected with exogenous DNA andgrown in culture, and include bacteria, fungal cells, and culturedhigher eukaryotic cells. Eukaryotic cells, particularly cultured cellsof multicellular organisms, are preferred. Techniques for manipulatingcloned DNA molecules and introducing exogenous DNA into a variety ofhost cells are disclosed by Sambrook et al., Molecular Cloning: ALaboratory Manual, 2nd ed., Cold Spring Harbor Laboratory Press, ColdSpring Harbor, N.Y., (1989), and Ausubel et al., ibid., which areincorporated herein by reference.

In general, a DNA sequence encoding a Zcytor11 soluble receptorpolypeptide, or a DNA sequence encoding an additional subunit of aheterodimeric or multimeric Zcytor11 soluble receptor, e.g., CRF2-4 orIL10R, polypeptide is operably linked to other genetic elements requiredfor its expression, generally including a transcription promoter andterminator, within an expression vector. The vector will also commonlycontain one or more selectable markers and one or more origins ofreplication, although those skilled in the art will recognize thatwithin certain systems selectable markers may be provided on separatevectors, and replication of the exogenous DNA may be provided byintegration into the host cell genome. Selection of promoters,terminators, selectable markers, vectors and other elements is a matterof routine design within the level of ordinary skill in the art. Manysuch elements are described in the literature and are available throughcommercial suppliers. Multiple components of a soluble receptor complexcan be co-transfected on individual expression vectors or be containedin a single expression vector. Such techniques of expressing multiplecomponents of protein complexes are well known in the art.

To direct a homodimeric, heterodimeric and multimeric Zcytor11 receptorpolypeptide into the secretory pathway of a host cell, a secretorysignal sequence (also known as a leader sequence, prepro sequence or presequence) is provided in the expression vector. The secretory signalsequence may be that of the receptor, or may be derived from anothersecreted protein (e.g., t-PA) or synthesized de novo. The secretorysignal sequence is joined to the Zcytor11 DNA sequence in the correctreading frame. Secretory signal sequences are commonly positioned 5′ tothe DNA sequence encoding the polypeptide of interest, although certainsignal sequences may be positioned elsewhere in the DNA sequence ofinterest (see, e.g., Welch et al., U.S. Pat. No. 5,037,743; Holland etal., U.S. Pat. No. 5,143,830).

Cultured mammalian cells are preferred hosts within the presentinvention. Methods for introducing exogenous DNA into mammalian hostcells include calcium phosphate-mediated transfection (Wigler et al.,Cell 14:725, (1978); Corsaro and Pearson, Somatic Cell Genetics 7:603,(1981): Graham and Van der Eb, Virology 52:456, (1973)), electroporation(Neumann et al., EMBO J. 1:841–845, (1982)), DEAE-dextran mediatedtransfection (Ausubel et al., eds., Current Protocols in MolecularBiology, (John Wiley and Sons, Inc., NY, 1987), and liposome-mediatedtransfection (Hawley-Nelson et al., Focus 15:73, (1993); Ciccarone etal., Focus 15:80, (1993)), which are incorporated herein by reference.The production of recombinant polypeptides in cultured mammalian cellsis disclosed, for example, by Levinson et al., U.S. Pat. No. 4,713,339;Hagen et al., U.S. Pat. No. 4,784,950; Palmiter et al., U.S. Pat. No.4,579,821; and Ringold, U.S. Pat. No. 4,656,134. Suitable culturedmammalian cells include the COS-1 (ATCC No. CRL 1650), COS-7 (ATCC No.CRL 1651), BHK (ATCC No. CRL 1632), BHK 570 (ATCC No. CRL 10314), 293(ATCC No. CRL 1573; Graham et al., J. Gen. Virol. 36:59–72, 1977) andChinese hamster ovary (e.g. CHO-K1; ATCC No. CCL 61) cell lines.Additional suitable cell lines are known in the art and available frompublic depositories such as the American Type Culture Collection,Rockville, Md. In general, strong transcription promoters are preferred,such as promoters from SV-40 or cytomegalovirus. See, e.g., U.S. Pat.No. 4,956,288. Other suitable promoters include those frommetallothionein genes (U.S. Pat. Nos. 4,579,821 and 4,601,978) and theadenovirus major late promoter.

Drug selection is generally used to select for cultured mammalian cellsinto which foreign DNA has been inserted. Such cells are commonlyreferred to as “transfectants”. Cells that have been cultured in thepresence of the selective agent and are able to pass the gene ofinterest to their progeny are referred to as “stable transfectants.” Apreferred selectable marker is a gene encoding resistance to theantibiotic neomycin. Selection is carried out in the presence of aneomycin-type drug, such as G-418 or the like. Selection systems mayalso be used to increase the expression level of the gene of interest, aprocess referred to as “amplification.” Amplification is carried out byculturing transfectants in the presence of a low level of the selectiveagent and then increasing the amount of selective agent to select forcells that produce high levels of the products of the introduced genes.A preferred amplifiable selectable marker is dihydrofolate reductase,which confers resistance to methotrexate. Other drug resistance genes(e.g. hygromycin resistance, multi-drug resistance, puromycinacetyltransferase) can also be used.

Other higher eukaryotic cells can also be used as hosts, includinginsect cells, plant cells and avian cells. Transformation of insectcells and production of foreign polypeptides therein is disclosed byGuarino et al., U.S. Pat. No. 5,162,222; Bang et al., U.S. Pat. No.4,775,624; and WIPO publication WO 94/06463, which are incorporatedherein by reference. The use of Agrobacterium rhizogenes as a vector forexpressing genes in plant cells has been reviewed by Sinkar et al., J.Biosci. (Bangalore) 11:47–58, (1987).

Fungal cells, including yeast cells, and particularly cells of the genusSaccharomyces, can also be used within the present invention, such asfor producing receptor fragments or polypeptide fusions. Methods fortransforming yeast cells with exogenous DNA and producing recombinantpolypeptides therefrom are disclosed by, for example, Kawasaki, U.S.Pat. No. 4,599,311; Kawasaki et al., U.S. Pat. No. 4,931,373; Brake,U.S. Pat. No. 4,870,008; Welch et al., U.S. Pat. No. 5,037,743; andMurray et al., U.S. Pat. No. 4,845,075. Transformed cells are selectedby phenotype determined by the selectable marker, commonly drugresistance or the ability to grow in the absence of a particularnutrient (e.g., leucine). A preferred vector system for use in yeast isthe POT1 vector system disclosed by Kawasaki et al. (U.S. Pat. No.4,931,373), which allows transformed cells to be selected by growth inglucose-containing media. Suitable promoters and terminators for use inyeast include those from glycolytic enzyme genes (see, e.g., Kawasaki,U.S. Pat. No. 4,599,311; Kingsman et al., U.S. Pat. No. 4,615,974; andBitter, U.S. Pat. No. 4,977,092) and alcohol dehydrogenase genes. Seealso U.S. Pat. Nos. 4,990,446; 5,063,154; 5,139,936 and 4,661,454.Transformation systems for other yeasts, including Hansenula polymorpha,Schizosaccharomyces pombe, Kluyveromyces lactis, Kluyveromyces fragilis,Ustilago maydis, Pichia pastoris, Pichia methanolica, Pichiaguillermondii and Candida maltosa are known in the art. See, forexample, Gleeson et al., J. Gen. Microbiol. 132:3459–3465, (1986) andCregg, U.S. Pat. No. 4,882,279. Aspergillus cells may be utilizedaccording to the methods of McKnight et al., U.S. Pat. No. 4,935,349.Methods for transforming Acremonium chrysogenum are disclosed by Suminoet al., U.S. Pat. No. 5,162,228. Methods for transforming Neurospora aredisclosed by Lambowitz, U.S. Pat. No. 4,486,533.

Transformed or transfected host cells are cultured according toconventional procedures in a culture medium containing nutrients andother components required for the growth of the chosen host cells. Avariety of suitable media, including defined media and complex media,are known in the art and generally include a carbon source, a nitrogensource, essential amino acids, vitamins and minerals. Media may alsocontain such components as growth factors or serum, as required. Thegrowth medium will generally select for cells containing the exogenouslyadded DNA by, for example, drug selection or deficiency in an essentialnutrient which is complemented by the selectable marker carried on theexpression vector or co-transfected into the host cell.

Within one aspect of the present invention, a novel soluble receptor ofthe present invention is produced by a cultured cell, and the cell isused to screen for ligands for the receptor, including the naturalligand, IL-TIF, as well as agonists and antagonists of the naturalligand. To summarize this approach, a cDNA or gene encoding the receptoris combined with other genetic elements required for its expression(e.g., a transcription promoter), and the resulting expression vector isinserted into a host cell. Cells that express the DNA and producefunctional receptor are selected and used within a variety of screeningsystems. Each component of the homodimeric, heterodimeric and multimericreceptor complex can be expressed in the same cell.

Mammalian cells suitable for use in expressing Zcytor11 receptors andtransducing a receptor-mediated signal include cells that express otherreceptor subunits which may form a functional complex with Zcytor11.These subunits may include those of the interferon receptor family or ofother class II or class I cytokine receptors, e.g., CRF2-4, IL-10R, andIL-9R. It is also preferred to use a cell from the same species as thereceptor to be expressed. Within a preferred embodiment, the cell isdependent upon an exogenously supplied hematopoietic growth factor forits proliferation. Preferred cell lines of this type are the human TF-1cell line (ATCC number CRL-2003) and the AML-193 cell line (ATCC numberCRL-9589), which are GM-CSF-dependent human leukemic cell lines and BaF3(Palacios and Steinmetz, Cell 41: 727–734, (1985)) which is an IL-3dependent murine pre-B cell line. Other cell lines include BHK, COS-1and CHO cells.

Suitable host cells can be engineered to produce the necessary receptorsubunits or other cellular component needed for the desired cellularresponse. This approach is advantageous because cell lines can beengineered to express receptor subunits from any species, therebyovercoming potential limitations arising from species specificity.Species orthologs of the human receptor cDNA can be cloned and usedwithin cell lines from the same species, such as a mouse cDNA in theBaF3 cell line. Cell lines that are dependent upon one hematopoieticgrowth factor, such as GM-CSF or IL-3, can thus be engineered to becomedependent upon IL-TIF.

Cells expressing functional receptor are used within screening assays. Avariety of suitable assays are known in the art. These assays are basedon the detection of a biological response in a target cell. One suchassay is a cell proliferation assay. Cells are cultured in the presenceor absence of a test compound, and cell proliferation is detected by,for example, measuring incorporation of tritiated thymidine or bycolorimetric assay based on the metabolic breakdown of3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT)(Mosman, J. Immunol. Meth. 65: 55–63, (1983)). An alternative assayformat uses cells that are further engineered to express a reportergene. The reporter gene is linked to a promoter element that isresponsive to the receptor-linked pathway, and the assay detectsactivation of transcription of the reporter gene. A preferred promoterelement in this regard is a serum response element, or SRE. See, e.g.,Shaw et al., Cell 56:563–572, (1989). A preferred such reporter gene isa luciferase gene (de Wet et al., Mol. Cell. Biol. 7:725, (1987)).Expression of the luciferase gene is detected by luminescence usingmethods known in the art (e.g., Baumgartner et al., J. Biol. Chem.269:29094–29101, (1994); Schenborn and Goiffin, Promega _(—) Notes41:11, 1993). Luciferase activity assay kits are commercially availablefrom, for example, Promega Corp., Madison, Wis. Target cell lines ofthis type can be used to screen libraries of chemicals, cell-conditionedculture media, fungal broths, soil samples, water samples, and the like.For example, a bank of cell-conditioned media samples can be assayed ona target cell to identify cells that produce ligand. Positive cells arethen used to produce a cDNA library in a mammalian expression vector,which is divided into pools, transfected into host cells, and expressed.Media samples from the transfected cells are then assayed, withsubsequent division of pools, re-transfection, subculturing, andre-assay of positive cells to isolate a cloned cDNA encoding the ligand.

A natural ligand for the Zcytor11 receptor can also be identified bymutagenizing a cell line expressing the full-length receptor andculturing it under conditions that select for autocrine growth. See WIPOpublication WO 95/21930. Within a typical procedure, IL-3 dependent BaF3cells expressing Zcytor11 and the necessary additional subunits aremutagenized, such as with 2-ethylmethanesulfonate (EMS). The cells arethen allowed to recover in the presence of IL-3, then transferred to aculture medium lacking IL-3 and IL-4. Surviving cells are screened forthe production of a IL-TIF, such as by adding soluble receptor to theculture medium or by assaying conditioned media on wild-type BaF3 cellsand BaF3 cells expressing the receptor. Using this method, cells andtissues expressing IL-TIF can be identified.

An additional screening approach provided by the present inventionincludes the use of hybrid receptor polypeptides. These hybridpolypeptides fall into two general classes. Within the first class, theintracellular domain of Zcytor11, comprising approximately residues 252to 574 of SEQ ID NO:2, is joined to the ligand-binding domain of asecond receptor. It is preferred that the second receptor be ahematopoietic cytokine receptor, such as mpl receptor (Souyri et al.,Cell 63: 1137–1147, (1990). The hybrid receptor will further comprise atransmembrane domain, which may be derived from either receptor. A DNAconstruct encoding the hybrid receptor is then inserted into a hostcell. Cells expressing the hybrid receptor are cultured in the presenceof a ligand for the binding domain and assayed for a response. Thissystem provides a means for analyzing signal transduction mediated byZcytor11 while using readily available ligands. This system can also beused to determine if particular cell lines are capable of responding tosignals transduced by Zcytor11 heterodimers and multimers of the presentinvention. A second class of hybrid receptor polypeptides comprise theextracellular (ligand-binding) domain of Zcytor11 (approximatelyresidues 18 to 228 of SEQ ID NO:2; SEQ ID NO:3) with an intracellulardomain of a second receptor, preferably a hematopoietic cytokinereceptor, and a transmembrane domain. Hybrid zacytor11 heterodimers andmultimers of the present invention receptors of this second class areexpressed in cells known to be capable of responding to signalstransduced by the second receptor. Together, these two classes of hybridreceptors enable the identification of a responsive cell type for thedevelopment of an assay for detecting a IL-TIF. Moreover, such cells canbe used in the presence of IL-TIF to assay the soluble receptorantagonists of the present invention in a competition-type assay. Insuch assay, a decrease in the proliferation or signal transductionactivity of IL-TIF in the presence of a soluble receptor of the presentinvention demonstrates antagonistic activity. Moreover IL-TIF-solublereceptor binding assays can be used to assess whether a soluble receptorantagonizes IL-TIF activity.

Cells found to express the ligand are then used to prepare a cDNAlibrary from which the ligand-encoding cDNA can be isolated as disclosedabove. The present invention thus provides, in addition to novelreceptor polypeptides, methods for cloning polypeptide ligands for thereceptors.

The tissue specificity of Zcytor11 expression suggests a role in thedevelopment of the pancreas, small intestine, colon and the thymus. Inview of the tissue specificity observed for this receptor, agonists(including the natural ligand) and antagonists have enormous potentialin both in vitro and in vivo applications. Compounds identified asreceptor agonists are useful for stimulating proliferation anddevelopment of target cells in vitro and in vivo. For example, agonistcompounds are useful as components of defined cell culture media, andmay be used alone or in combination with other cytokines and hormones toreplace serum that is commonly used in cell culture. Agonists orantagonist may be useful in specifically regulating the growth and/ordevelopment of pancreatic, gasto-intestinal or thymic-derived cells inculture. These compounds are useful as research reagents forcharacterizing sites of ligand-receptor interaction. In vivo, receptoragonists or antagonists may find application in the treatmentpancreatic, gastro-intestinal or thymic diseases.

Agonists or antagonists to Zcytor11 may include small families ofpeptides. These peptides may be identified employing affinity selectionconditions that are known in the art, from a population of candidatespresent in a peptide library. Peptide libraries include combinatorylibraries chemically synthesized and presented on solid support (Lam etal., Nature 354: 82–84 (1991)) or are in solution (Houghten et al.,BioTechniques 13: 412–421, (1992)), expressed then linked to plasmid DNA(Cull et al., Proc. Natl. Acad. Sci. USA 89: 1865–1869 (1992)) orexpressed and subsequently displayed on the surfaces of viruses or cells(Boder and Wittrup, Nature Biotechnology 15: 553–557(1997); Cwirla etal. Science 276: 1696–1699 (1997)).

Zcytor11 homodimeric, heterodimeric and multimeric may also be usedwithin diagnostic systems for the detection of circulating levels ofIL-TIF ligand. Within a related embodiment, antibodies or other agentsthat specifically bind to Zcytor11 soluble receptors of the presentinvention can be used to detect circulating receptor polypeptides.Elevated or depressed levels of ligand or receptor polypeptides may beindicative of pathological conditions, including cancer.

Zcytor11 homodimeric, heterodimeric and multimeric receptor polypeptidescan be prepared by expressing a truncated DNA encoding the extracellulardomain, for example, a polypeptide which contains SEQ ID NO:3 or thecorresponding region of a non-human receptor. It is preferred that theextracellular domain polypeptides be prepared in a form substantiallyfree of transmembrane and intracellular polypeptide segments. Forexample, the C-terminus of the receptor polypeptide may be at residue228 of SEQ ID NO:2 or the corresponding region of an allelic variant ora non-human receptor. To direct the export of the receptor domain fromthe host cell, the receptor DNA is linked to a second DNA segmentencoding a secretory peptide, such as a t-PA secretory peptide. Tofacilitate purification of the secreted receptor domain, a C-terminalextension, such as a poly-histidine tag, substance P, Flag™ peptide{Hopp et al., Biotechnology 6:1204–1210, (1988); available from EastmanKodak Co., New Haven, Conn.) or another polypeptide or protein for whichan antibody or other specific binding agent is available, can be fusedto the receptor polypeptide. Moreover, heterodimeric and multimericnon-zcytor11 subunit extracellular cytokine binding domains are a alsoprepared as above.

In an alternative approach, a receptor extracellular domain of zcytor11or other class I or II cytokine receptor component can be expressed as afusion with immunoglobulin heavy chain constant regions, typically anF_(c) fragment, which contains two constant region domains and a hingeregion but lacks the variable region (See, Sledziewski, A Z et al., U.S.Pat. Nos. 6,018,026 and 5,750,375). The soluble zcytor11, solublezcytor11/CRF2-4 heterodimers and multimers of the present inventioninclude such fusions. Such fusions are typically secreted as multimericmolecules wherein the Fc portions are disulfide bonded to each other andtwo receptor polypeptides are arrayed in closed proximity to each other.Fusions of this type can be used to affinity purify the cognate ligandfrom solution, as an in vitro assay tool, to block signals in vitro byspecifically titrating out ligand, and as antagonists in vivo byadministering them parenterally to bind circulating ligand and clear itfrom the circulation. To purify ligand, a Zcytor11-Ig chimera is addedto a sample containing the ligand (e.g., cell-conditioned culture mediaor tissue extracts) under conditions that facilitate receptor-ligandbinding (typically near-physiological temperature, pH, and ionicstrength). The chimera-ligand complex is then separated by the mixtureusing protein A, which is immobilized on a solid support (e.g.,insoluble resin beads). The ligand is then eluted using conventionalchemical techniques, such as with a salt or pH gradient. In thealternative, the chimera itself can be bound to a solid support, withbinding and elution carried out as above. The chimeras may be used invivo to regulate gastrointestinal, pancreatic or thymic functions.Chimeras with high binding affinity are administered parenterally (e.g.,by intramuscular, subcutaneous or intravenous injection). Circulatingmolecules bind ligand and are cleared from circulation by normalphysiological processes. For use in assays, the chimeras are bound to asupport via the F_(c) region and used in an ELISA format.

The present invention further provides a variety of other polypeptidefusions and related multimeric proteins comprising one or morepolypeptide fusions. For example, a soluble zcytor11 receptor or solublezcytor11 heterodimeric polypeptide, such as soluble zcytor11/CRF2-4 canbe prepared as a fusion to a dimerizing protein as disclosed in U.S.Pat. Nos. 5,155,027 and 5,567,584. Preferred dimerizing proteins in thisregard include immunoglobulin constant region domains, e.g., IgGγ1, andthe human κ light chain. Immunoglobulin-soluble zcytor11 receptor orimmunoglobulin-soluble zcytor11 heterodimeric polypeptide, such asimmunoglobulin-soluble zcytor11/CRF2-4 fusions can be expressed ingenetically engineered cells to produce a variety of multimeric zcytor11receptor analogs. Auxiliary domains can be fused to soluble zcytor11receptor or soluble zcytor11 heterodimeric polypeptide, such as solublezcytor11/CRF2-4 to target them to specific cells, tissues, ormacromolecules (e.g., collagen, or cells expressing the IL-TIF). Azcytor11 polypeptide can be fused to two or more moieties, such as anaffinity tag for purification and a targeting domain. Polypeptidefusions can also comprise one or more cleavage sites, particularlybetween domains. See, Tuan et al., Connective Tissue Research 34:1–9,1996.

A preferred assay system employing a ligand-binding receptor fragmentuses a commercially available biosensor instrument (BIAcore™, PharmaciaBiosensor, Piscataway, N.J.), wherein the receptor fragment isimmobilized onto the surface of a receptor chip. Use of this instrumentis disclosed by Karlsson, J. Immunol. Methods 145:229–240, (1991) andCunningham and Wells, J. Mol. Biol. 234:554–563, (1993). A receptorfragment is covalently attached, using amine or sulfhydryl chemistry, todextran fibers that are attached to gold film within the flow cell. Atest sample is passed through the cell. If ligand is present in thesample, it will bind to the immobilized receptor polypeptide, causing achange in the refractive index of the medium, which is detected as achange in surface plasmon resonance of the gold film. This system allowsthe determination of on- and off-rates, from which binding affinity canbe calculated, and assessment of stoichiometry of binding.

Ligand-binding receptor polypeptides can also be used within other assaysystems known in the art. Such systems include Scatchard analysis fordetermination of binding affinity. See, Scatchard, Ann. NY Acad. Sci.51: 660–672, (1949) and calorimetric assays (Cunningham et al., Science253:545–548, (1991); Cunningham et al., Science 254:821–825, (1991)).

A receptor ligand-binding polypeptide can also be used for purificationof 1L-TIF ligand. The receptor polypeptide is immobilized on a solidsupport, such as beads of agarose, cross-linked agarose, glass,cellulosic resins, silica-based resins, polystyrene, cross-linkedpolyacrylamide, or like materials that are stable under the conditionsof use. Methods for linking polypeptides to solid supports are known inthe art, and include amine chemistry, cyanogen bromide activation,N-hydroxysuccinimide activation, epoxide activation, sulfhydrylactivation, and hydrazide activation. The resulting media will generallybe configured in the form of a column, and fluids containing ligand arepassed through the column one or more times to allow ligand to bind tothe receptor polypeptide. The ligand is then eluted using changes insalt concentration or pH to disrupt ligand-receptor binding.

Moreover, soluble zcytor11 receptor or soluble zcytor11 heterodimericreceptor polypeptides, such as soluble zcytor11/CRF2-4, can be used as a“ligand sink,” i.e., antagonist, to bind ligand in vivo or in vitro intherapeutic or other applications where the presence of the ligand isnot desired. For example, in cancers that are expressing large amountsof bioactive IL-TIF, soluble zcytor11 receptor or soluble zcytor11heterodimeric and multimeric receptor polypeptides, such as solublezcytor11/CRF2-4 can be used as a direct antagonist of the ligand invivo, and may aid in reducing progression and symptoms associated withthe disease, and can be used in conjunction with other therapies (e.g.,chemotherapy) to enhance the effect of the therapy in reducingprogression and symptoms, and preventing relapse. Moreover, solublezcytor11 receptor or soluble zcytor11 heterodimeric receptorpolypeptides, such as soluble zcytor11/CRF2-4 can be used to slow theprogression of cancers that over-express zcytor11 receptors, by bindingligand in vivo that would otherwise enhance proliferation of thosecancers.

Moreover, soluble zcytor11 receptor or soluble zcytor11 heterodimericreceptor polypeptides, such as soluble zcytor11/CRF2-4 can be used invivo or in diagnostic applications to detect IL-TF-expressing cancers invivo or in tissue samples. For example, the soluble zcytor11 receptor orsoluble zcytor11 heterodimeric receptor polypeptides, such as solublezcytor11/CRF2-4 can be conjugated to a radio-label or fluorescent labelas described herein, and used to detect the presence of the IL-TIF in atissue sample using an in vitro ligand-receptor type binding assay, orfluorescent imaging assay. Moreover, a radiolabeled soluble zcytor11receptor or soluble zcytor11 heterodimeric receptor polypeptides, suchas soluble zcytor11/CRF2-4 could be administered in vivo to detectLigand-expressing solid tumors through a radio-imaging method known inthe art.

Soluble zcytor11 receptor or soluble zcytor11 heterodimeric polypeptide,such as soluble zcytor11/CRF2-4 polypeptides can also be used to prepareantibodies that bind to epitopes, peptides, or polypeptides containedwithin the antigen. The zcytor11 polypeptide or a fragment thereofserves as an antigen (immunogen) to inoculate an animal and elicit animmune response. One of skill in the art would recognize that antigensor immunogenic epitopes can consist of stretches of amino acids within alonger polypeptide, from about 10 amino acids and up to about the entirelength of the polypeptide or longer depending on the polypeptide.Suitable antigens include the zcytor11 polypeptide encoded by SEQ IDNO:3 or a contiguous 9 to 211 AA amino acid fragment thereof. Preferredpeptides to use as antigens are the cytokine binding domain, disclosedherein, and zcytor11 hydrophilic peptides such as those predicted by oneof skill in the art from a hydrophobicity plot, determined for example,from a Hopp/Woods hydrophilicity profile based on a sliding six-residuewindow, with buried G, S, and T residues and exposed H, Y, and Wresidues ignored, or from a Jameson-Wolf plot of SEQ ID NO:3 using aDNA*STAR program. In addition, conserved motifs, and variable regionsbetween conserved motifs of zcytor11 soluble receptor are suitableantigens. Suitable antigens also include the zcytor11 polypeptidesdisclosed above in combination with another class I or II cytokineextracellular domain, such as those that form soluble zcytor11heterodimeric polypeptides, such as soluble zcytor11/CRF2-4. Moreover,corresponding regions of the mouse soluble zcytor11 receptor polypeptide(SEQ ID NO:3) can be used to generate antibodies against the solublemouse zcytor11 receptor. In addition Antibodies generated from thisimmune response can be isolated and purified as described herein.Methods for preparing and isolating polyclonal and monoclonal antibodiesare well known in the art. See, for example, Current Protocols inImmunology, Cooligan, et al. (eds.), National Institutes of Health, JohnWiley and Sons, Inc., 1995; Sambrook et al., Molecular Cloning: ALaboratory Manual, Second Edition, Cold Spring Harbor, N.Y., 1989; andHurrell, J. G. R., Ed., Monoclonal Hybridoma Antibodies: Techniques andApplications, CRC Press, Inc., Boca Raton, Fla., 1982.

As would be evident to one of ordinary skill in the art, polyclonalantibodies can be generated from inoculating a variety of warm-bloodedanimals such as horses, cows, goats, sheep, dogs, chickens, rabbits,mice, and rats with a soluble zcytor11 receptor or soluble zcytor11heterodimeric polypeptide, such as soluble zcytor11/CRF2-4 polypeptideor a fragment thereof. The immunogenicity of a zcytor11 polypeptide maybe increased through the use of an adjuvant, such as alum (aluminumhydroxide) or Freund's complete or incomplete adjuvant. Polypeptidesuseful for immunization also include fusion polypeptides, such asfusions of zcytor11 or a portion thereof with an immunoglobulinpolypeptide or with maltose binding protein. The polypeptide immunogenmay be a full-length molecule or a portion thereof. If the polypeptideportion is “hapten-like”, such portion may be advantageously joined orlinked to a macromolecular carrier (such as keyhole limpet hemocyanin(KLH), bovine serum albumin (BSA) or tetanus toxoid) for immunization.

As used herein, the term “antibodies” includes polyclonal antibodies,affinity-purified polyclonal antibodies, monoclonal antibodies, andantigen-binding fragments, such as F(ab′)₂ and Fab proteolyticfragments. Genetically engineered intact antibodies or fragments, suchas chimeric antibodies, Fv fragments, single chain antibodies and thelike, as well as synthetic antigen-binding peptides and polypeptides,are also included. Non-human antibodies may be humanized by graftingnon-human CDRs onto human framework and constant regions, or byincorporating the entire non-human variable domains (optionally“cloaking” them with a human-like surface by replacement of exposedresidues, wherein the result is a “veneered” antibody). In someinstances, humanized antibodies may retain non-human residues within thehuman variable region framework domains to enhance proper bindingcharacteristics. Through humanizing antibodies, biological half-life maybe increased, and the potential for adverse immune reactions uponadministration to humans is reduced.

Antibodies are considered to be specifically binding if: 1) they exhibita threshold level of binding activity, and 2) they do not significantlycross-react with related polypeptide molecules. A threshold level ofbinding is determined if anti-soluble zcytor11 receptor or anti-solublezcytor11 heterodimeric polypeptide, such as anti-soluble zcytor11/CRF2-4antibodies herein bind to a soluble zcytor11 receptor or solublezcytor11 heterodimeric polypeptide, such as soluble zcytor11/CRF2-4polypeptide, peptide or epitope with an affinity at least 10-foldgreater than the binding affinity to control (non-soluble zcytor11receptor or soluble zcytor11 heterodimeric polypeptide, such as solublezcytor11/CRF2-4) polypeptide. It is preferred that the antibodiesexhibit a binding affinity (K_(a)) of 10⁶ M⁻¹ or greater, preferably 10⁷M⁻¹ or greater, more preferably 10⁸ M⁻¹ or greater, and most preferably10⁹ M⁻¹ or greater. The binding affinity of an antibody can be readilydetermined by one of ordinary skill in the art, for example, byScatchard analysis (Scatchard, G., Ann. NY Acad. Sci. 51: 660–672,1949).

Whether anti-soluble zcytor11 receptor or anti-soluble zcytor11heterodimeric polypeptide, such as anti-soluble zcytor11/CRF2-4antibodies do not significantly cross-react with related polypeptidemolecules is shown, for example, by the antibody detecting solublezcytor11 receptor or soluble zcytor11 heterodimeric polypeptide, such assoluble zcytor11/CRF2-4 polypeptide but not known related polypeptidesusing a standard Western blot analysis (Ausubel et al., ibid.). Examplesof known related polypeptides are those disclosed in the prior art, suchas known orthologs, and paralogs, and similar known members of a proteinfamily. Screening can also be done using non-human soluble zcytor11receptor or soluble zcytor11 heterodimeric polypeptide, such as solublezcytor11/CRF2-4, and soluble zcytor11 receptor or soluble zcytor11heterodimeric polypeptide, such as soluble zcytor11/CRF2-4 mutantpolypeptides. Moreover, antibodies can be “screened against” knownrelated polypeptides, to isolate a population that specifically binds tothe soluble zcytor11 receptor or soluble zcytor11 heterodimericpolypeptide, such as soluble zcytor11/CRF2-4 polypeptides. For example,antibodies raised to soluble zcytor11 receptor or soluble zcytor11heterodimeric polypeptide, such as soluble zcytor11/CRF2-4 are adsorbedto related polypeptides adhered to insoluble matrix; antibodies specificto soluble zcytor11 receptor or soluble zcytor11 heterodimericpolypeptide, such as soluble zcytor11/CRF2-4 will flow through thematrix under the proper buffer conditions. Screening allows isolation ofpolyclonal and monoclonal antibodies non-crossreactive to known closelyrelated polypeptides (Antibodies: A Laboratory Manual, Harlow and Lane(eds.), Cold Spring Harbor Laboratory Press, 1988; Current Protocols inImmunology, Cooligan, et al. (eds.), National Institutes of Health, JohnWiley and Sons, Inc., 1995). Screening and isolation of specificantibodies is well known in the art. See, Fundamental Immunology, Paul(eds.), Raven Press, 1993; Getzoff et al., Adv. in Immunol. 43: 1–98,1988; Monoclonal Antibodies: Principles and Practice, Goding, J. W.(eds.), Academic Press Ltd., 1996; Benjamin et al., Ann. Rev. Immunol.2: 67–101, 1984. Specifically binding anti-soluble zcytor11 receptor oranti-soluble zcytor11 heterodimeric polypeptide, such as anti-solublezcytor11/CRF2-4 antibodies can be detected by a number of methods in theart, and disclosed below.

A variety of assays known to those skilled in the art can be utilized todetect antibodies that bind to soluble zcytor11 receptor or solublezcytor11 heterodimeric polypeptide, such as soluble zcytor11/CRF2-4proteins or polypeptides. Exemplary assays are described in detail inAntibodies: A Laboratory Manual, Harlow and Lane (Eds.), Cold SpringHarbor Laboratory Press, 1988. Representative examples of such assaysinclude: concurrent immunoelectrophoresis, radioimmunoassay,radioimmuno-precipitation, enzyme-linked immunosorbent assay (ELISA),dot blot or Western blot assay, inhibition or competition assay, andsandwich assay. In addition, antibodies can be screened for binding towild-type versus mutant soluble zcytor11 receptor or soluble zcytor11heterodimeric polypeptide, such as soluble zcytor11/CRF2-4 protein orpolypeptide.

Alternative techniques for generating or selecting antibodies usefulherein include in vitro exposure of lymphocytes to soluble zcytor11receptor or soluble zcytor11 heterodimeric polypeptide, such as solublezcytor11/CRF2-4 protein or peptide, and selection of antibody displaylibraries in phage or similar vectors (for instance, through use ofimmobilized or labeled soluble zcytor11 receptor or soluble zcytor11heterodimeric polypeptide, such as soluble zcytor11/CRF2-4 protein orpeptide). Genes encoding polypeptides having potential binding domainsfor soluble zcytor11 receptor or soluble zcytor11 heterodimericpolypeptide, such as soluble zcytor11/CRF2-4 polypeptide, can beobtained by screening random peptide libraries displayed on phage (phagedisplay) or on bacteria, such as E. coli. Nucleotide sequences encodingthe polypeptides can be obtained in a number of ways, such as throughrandom mutagenesis and random polynucleotide synthesis. These randompeptide display libraries can be used to screen for peptides whichinteract with a known target which can be a protein or polypeptide, suchas a ligand or receptor, a biological or synthetic macromolecule, ororganic or inorganic substances. Techniques for creating and screeningsuch random peptide display libraries are known in the art (Ladner etal., U.S. Pat. No. 5,223,409; Ladner et al., U.S. Pat. No. 4,946,778;Ladner et al., U.S. Pat. No. 5,403,484 and Ladner et al., U.S. Pat. No.5,571,698) and random peptide display libraries and kits for screeningsuch libraries are available commercially, for instance from Clontech(Palo Alto, Calif.), Invitrogen Inc. (San Diego, Calif.), New EnglandBiolabs, Inc. (Beverly, Mass.) and Pharmacia LKB Biotechnology Inc.(Piscataway, N.J.). Random peptide display libraries can be screenedusing the soluble zcytor11 receptor or soluble zcytor11 heterodimericpolypeptide, such as soluble zcytor11/CRF2-4 sequences disclosed hereinto identify proteins which bind to soluble zcytor11 receptor or solublezcytor11 heterodimeric polypeptide, such as soluble zcytor11/CRF2-4.These “binding polypeptides” which interact with soluble zcytor11receptor or soluble zcytor11 heterodimeric polypeptide, such as solublezcytor11/CRF2-4 polypeptides can be used for tagging cells; forisolating homolog polypeptides by affinity purification; they can bedirectly or indirectly conjugated to drugs, toxins, radionuclides andthe like. These binding polypeptides can also be used in analyticalmethods such as for screening expression libraries and neutralizingactivity, e.g., for blocking interaction between IL-TIF ligand andreceptor, or viral binding to a receptor. The binding polypeptides canalso be used for diagnostic assays for determining circulating levels ofsoluble zcytor11 receptor or soluble zcytor11 heterodimeric polypeptide,such as soluble zcytor11/CRF2-4 polypeptides; for detecting orquantitating soluble zcytor11 receptor or soluble zcytor11 heterodimericpolypeptide, such as soluble zcytor11/CRF2-4 polypeptides as marker ofunderlying pathology or disease. These binding polypeptides can also actas zcytor11 receptor or zcytor11 heterodimeric polypeptide, such aszcytor11/CRF2-4 “antagonists” to block zcytor11 receptor or zcytor11heterodimeric polypeptide, such as zcytor11/CRF2-4 binding and signaltransduction in vitro and in vivo. Again, these anti-soluble zcytor11receptor or anti-soluble zcytor11 heterodimeric polypeptide, such asanti-soluble zcytor11/CRF2-4 binding polypeptides would be useful forinhibiting IL-TIF activity, as well as receptor activity orprotein-binding. Antibodies raised to the heterodimer or multimericcombinations of the present invention are preferred embodiments, as theymay act more specifically against the IL-TIF, or more potently thanantibodies raised to only one subunit. Moreover, the antagonistic andbinding activity of the antibodies of the present invention can beassayed in the IL-TIF proliferation and other biological assaysdescribed herein.

Antibodies to soluble zcytor11 receptor or soluble zcytor11heterodimeric polypeptide, such as soluble zcytor11/CRF2-4 may be usedfor tagging cells that express zcytor11 receptor or zcytor11heterodimeric polypeptides, such as zcytor11/CRF2-4; for isolatingsoluble zcytor11 receptor or soluble zcytor11 heterodimeric polypeptide,such as soluble zcytor11/CRF2-4 polypeptide by affinity purification;for diagnostic assays for determining circulating levels of solublezcytor11 receptor or soluble zcytor11 heterodimeric polypeptide, such assoluble zcytor11/CRF2-4 polypeptides; for detecting or quantitatingsoluble zcytor11 receptor or soluble zcytor11 heterodimeric polypeptide,such as soluble zcytor11/CRF2-4 as marker of underlying pathology ordisease; in analytical methods employing FACS; for screening expressionlibraries; for generating anti-idiotypic antibodies; and as neutralizingantibodies or as antagonists to block zcytor11 receptor or zcytor11heterodimeric polypeptide, such as zcytor11/CRF2-4, or IL-TIF activityin vitro and in vivo. Suitable direct tags or labels includeradionuclides, enzymes, substrates, cofactors, inhibitors, fluorescentmarkers, chemiluminescent markers, magnetic particles and the like;indirect tags or labels may feature use of biotin-avidin or othercomplement/anti-complement pairs as intermediates. Antibodies herein mayalso be directly or indirectly conjugated to drugs, toxins,radionuclides and the like, and these conjugates used for in vivodiagnostic or therapeutic applications. Moreover, antibodies to solublezcytor11 receptor or soluble zcytor11 heterodimeric polypeptide, such assoluble zcytor11/CRF2-4 or fragments thereof may be used in vitro todetect denatured or non-denatured soluble zcytor11 receptor or solublezcytor11 heterodimeric polypeptide, such as soluble zcytor11/CRF2-4 orfragments thereof in assays, for example, Western Blots or other assaysknown in the art.

Antibodies to soluble zcytor11 receptor or soluble zcytor11heterodimeric polypeptide, such as soluble zcytor11/CRF2-4 are usefulfor tagging cells that express the corresponding receptors and assayingtheir expression levels, for affinity purification, within diagnosticassays for determining circulating levels of soluble receptorpolypeptides, analytical methods employing fluorescence-activated cellsorting. Moreover, divalent antibodies, and anti-idiotypic antibodiesmay be used as agonists to mimic the effect of the IL-TIF.

Antibodies herein can also be directly or indirectly conjugated todrugs, toxins, radionuclides and the like, and these conjugates used forin vivo diagnostic or therapeutic applications. For instance, antibodiesor binding polypeptides which recognize soluble zcytor11 receptor orsoluble zcytor11 heterodimeric polypeptide, such as solublezcytor11/CRF2-4 polypeptides of the present invention can be used toidentify or treat tissues or organs that express a correspondinganti-complementary molecule (i.e., a zcytor11 receptor, or zcytor11heterodimeric receptor, such as zcytor11/CRF2-4). More specifically,anti- soluble zcytor11 receptor or anti-soluble zcytor11 heterodimericpolypeptide, such as anti-soluble zcytor11/CRF2-4 antibodies, orbioactive fragments or portions thereof, can be coupled to detectable orcytotoxic molecules and delivered to a mammal having cells, tissues ororgans that express the zcytor11 receptor or a zcytor11 heterodimericreceptor, such as zcytor11/CRF2-4 receptor molecules.

Suitable detectable molecules may be directly or indirectly attached topolypeptides that bind soluble zcytor11 receptor or soluble zcytor11heterodimeric polypeptide, such as soluble zcytor11/CRF2-4 (“bindingpolypeptides,” including binding peptides disclosed above), antibodies,or bioactive fragments or portions thereof. Suitable detectablemolecules include radionuclides, enzymes, substrates, cofactors,inhibitors, fluorescent markers, chemiluminescent markers, magneticparticles and the like. Suitable cytotoxic molecules may be directly orindirectly attached to the polypeptide or antibody, and includebacterial or plant toxins (for instance, diphtheria toxin, Pseudomonasexotoxin, ricin, abrin and the like), as well as therapeuticradionuclides, such as iodine-131, rhenium-188 or yttrium-90 (eitherdirectly attached to the polypeptide or antibody, or indirectly attachedthrough means of a chelating moiety, for instance). Binding polypeptidesor antibodies may also be conjugated to cytotoxic drugs, such asadriamycin. For indirect attachment of a detectable or cytotoxicmolecule, the detectable or cytotoxic molecule can be conjugated with amember of a complementary/anticomplementary pair, where the other memberis bound to the binding polypeptide or antibody portion. For thesepurposes, biotin/streptavidin is an exemplarycomplementary/anticomplementary pair.

In another embodiment, binding polypeptide-toxin fusion proteins orantibody-toxin fusion proteins can be used for targeted cell or tissueinhibition or ablation (for instance, to treat cancer cells or tissues).Alternatively, if the binding polypeptide has multiple functionaldomains (i.e., an activation domain or a ligand binding domain, plus atargeting domain), a fusion protein including only the targeting domainmay be suitable for directing a detectable molecule, a cytotoxicmolecule or a complementary molecule to a cell or tissue type ofinterest. In instances where the fusion protein including only a singledomain includes a complementary molecule, the anti-complementarymolecule can be conjugated to a detectable or cytotoxic molecule. Suchdomain-complementary molecule fusion proteins thus represent a generictargeting vehicle for cell/tissue-specific delivery of genericanti-complementary-detectable/cytotoxic molecule conjugates.

In another embodiment, soluble zcytor11 receptor or soluble zcytor11heterodimeric polypeptide, such as soluble zcytor11/CRF2-4 bindingpolypeptide-cytokine or antibody-cytokine fusion proteins can be usedfor enhancing in vivo killing of target tissues (for example,pancreatic, blood, lymphoid, colon, and bone marrow cancers), if thebinding polypeptide-cytokine or anti-soluble zcytor11 receptor oranti-soluble zcytor11 heterodimeric polypeptide, such as anti-solublezcytor11/CRF2-4 antibody targets the hyperproliferative cell (See,generally, Hornick et al., Blood 89:4437–47, 1997). The described fusionproteins enable targeting of a cytokine to a desired site of action,thereby providing an elevated local concentration of cytokine. Suitableanti-zcytor11 homodimer and heterodimer antibodies target an undesirablecell or tissue (i.e., a tumor or a leukemia), and the fused cytokinemediates improved target cell lysis by effector cells. Suitablecytokines for this purpose include interleukin 2 andgranulocyte-macrophage colony-stimulating factor (GM-CSF), for instance.

Alternatively, soluble zcytor11 receptor or soluble zcytor11heterodimeric polypeptide, such as soluble zcytor11/CRF2-4 bindingpolypeptide or antibody fusion proteins described herein can be used forenhancing in vivo killing of target tissues by directly stimulating azcytor11 receptor-modulated apoptotic pathway, resulting in cell deathof hyperproliferative cells expressing zcytor11 receptor or a zcytor11heterodimeric receptor, such as soluble zcytor11/CRF2-4 receptor.

The invention is further illustrated by the following non-limitingexamples.

EXAMPLE 1 Construction of Mammalian Expression Vectors That Expresszcytor11 Soluble Receptors: zcytor11CEE, zcytor11CFLG, zcytor11CHIS andzcytor11-Fc4

A. Construction of zcytor11 Mammalian Expression Vector Containingzcytor11CEE, zcytor11CFLG and zcytor11CHIS

An expression vector is prepared for the expression of the soluble,extracellular domain of the zcytor11 polypeptide (SEQ ID NO:3),pC4zcytor11CEE, wherein the construct is designed to express a zcytor11polypeptide comprised of the predicted initiating methionine andtruncated adjacent to the predicted transmembrane domain, and with aC-terminal Glu-Glu tag (SEQ ID NO:4).

A zcytor11 DNA fragment comprising the zcytor11 extracellular cytokinebinding domain (SEQ ID NO:3) is created using PCR, and purified. Theexcised DNA is subcloned into a plasmid expression vector that has asignal peptide, e.g., the native zcytor11 signal peptide, and attaches aGlu-Glu tag (SEQ ID NO:4) to the C-terminus of the zcytor11polypeptide-encoding polynucleotide sequence. Such an expression vectormammalian expression vector contains an expression cassette having amammalian promoter, multiple restriction sites for insertion of codingsequences, a stop codon and a mammalian terminator. The plasmid can alsohave an E. coli origin of replication, a mammalian selectable markerexpression unit having an SV40 promoter, enhancer and origin ofreplication, a DHFR gene and the SV40 terminator.

Restriction digested zcytor11 insert and previously digested vector areligated using standard molecular biological techniques, andelectroporated into competent cells such as DH10B competent cells (GIBCOBRL, Gaithersburg, Md.) according to manufacturer's direction and platedonto LB plates containing 50 mg/ml ampicillin, and incubated overnight.Colonies are screened by restriction analysis of DNA prepared fromindividual colonies. The insert sequence of positive clones is verifiedby sequence analysis. A large scale plasmid preparation is done using aQIAGEN® Maxi prep kit (Qiagen) according to manufacturer's instructions.

The same process is used to prepare the zcytor11 soluble homodimeric,heterodimeric or multimeric receptors (including non-zcytor 1 solublereceptor subunits, such as, soluble CRF2-4 or IL-10R) with a C-terminalhis tag, composed of 6 His residues in a row; and a C-terminal flag (SEQID NO:5) tag, zcytor11CFLAG. To construct these constructs, theaforementioned vector has either the HIS or the FLAG® tag in place ofthe glu-glu tag (SEQ ID NO:4).

B. Mammalian Expression Construction of Soluble zcytor11 Receptorzcytor11-Fc4

An expression plasmid containing all or part of a polynucleotideencoding zcytor11 is constructed via homologous recombination. Afragment of zcytor11 cDNA was isolated using PCR that includes thepolynucleotide sequence from extracellular domain of the zcytor11receptor. Primers used in PCR for the production of the zcytor11fragment are from 5′ to 3′ end: (1) about 40 bp of the vector flankingsequence (5′ of the insert) and about17 bp corresponding to the 5′ endof the zcytor11 extracellular domain; and (2) about 40 bp of the 5′ endof the Fc4 polynucleotide sequence (SEQ ID NO:6) and about 17 bpcorresponding to the 3′ end of the zcytor11 extracellular domain. Thefragment of Fc4 for fusion with the zcytor11 is generated by PCR in asimilar fashion. The two primers used in the production of the Fc4fragment include: (1) a 5′ primer consisting of about 40 bp of sequencefrom the 3′ end of zcytor11 extracellular domain and about 17 bp of the5′ end of Fc4 (SEQ ID NO:6); and (2) a 3′ primer consisting of about 40bp of vector sequence (3′ of the insert) and about 17 bp of the 3′ endof Fc4 (SEQ ID NO:6). PCR amplification of the each of the reactionsdescribed above is then performed using conditions standard in the art.

An exemplary expression vector is derived from the plasmid pCZR199(deposited at the American Type Culture Collection, 10801 UniversityBoulevard, Manassas, Va. 20110-2209, designated No. 98668), that is cutwith SmaI (BRL). The expression vector was derived from the plasmidpCZR199, and is a mammalian expression vector containing an expressioncassette having the CMV immediate early promoter, a consensus intronfrom the variable region of mouse immunoglobulin heavy chain locus,multiple restriction sites for insertion of coding sequences, a stopcodon and a human growth hormone terminator. The expression vector alsohas an E. coli origin of replication, a mammalian selectable markerexpression unit having an SV40 promoter, enhancer and origin ofreplication, a DHFR gene and the SV40 terminator. The expression vectorused was constructed from pCZR199 by the replacement of themetallothionein promoter with the CMV immediate early promoter.

Competent yeast cells (S. cerevisiae) are combined with approximately 1μg each of the zcytor11 and Fc4 inserts, and 100 ng of SmaI (BRL)digested expression vector and electroporated. The yeast/DNA mixturesare electropulsed at, for example, 0.75 kV (5 kV/cm), “infinite” ohms,25 μF. To each cuvette is added 600 μl of 1.2 M sorbitol and the yeastwas plated in aliquots onto URA-D plates and incubated at 30° C.

After about 48 hours, the Ura+ yeast transformants from a single plateare picked, DNA isolated, and transformed into electrocompetent E. colicells (e.g., DH10B, GibcoBRL), and plated using standard procedures.Individual clones harboring the correct expression construct forzcytor11-Fc4 are identified by restriction digest to verify the presenceof the zcytor11-Fc4 insert and to confirm that the various DNA sequenceshave been joined correctly to one another. The insert of positive clonesis subjected to sequence analysis. Larger scale plasmid DNA is isolatedusing the Qiagen Maxi kit (Qiagen) according to manufacturer'sinstructions.

Similar methods are used to prepare non-zcytor11 subunits ofheterodimeric and multimeric receptors, such as CRF2-4 and IL-10R taggedwith Fc4.

EXAMPLE 2 Transfection and Expression of Soluble Receptor Polypeptides

BHK 570 cells (ATCC No. CRL-10314), DG-44 CHO, or other mammalian cellsare plated at about 1.2×10⁶ cells/well (6-well plate) in 800 μl ofappropriate serum free (SF) media (e.g., DMEM, Gibco/BRL High Glucose)(Gibco BRL, Gaithersburg, Md.). The cells are transfected withexpression plasmids containing zcytor11CEE, zcytor11CFLG, zcytor11CHISor zcytor11-Fc4 (Example 1), or non-zcytor11 subunits of heterodimericand multimeric receptors, such as -CEE, -CFLG, -CHIS, or -Fc4 taggedCRF2-4 and IL-10R, using Lipofectin™ (Gibco BRL), in serum free (SF)media according to manufacturer's instruction. Single clones expressingthe soluble receptors are isolated, screened and grown up in cellculture media, and purified using standard techniques.

EXAMPLE 3 Expression of zcytor11 Soluble Receptor in E. coli

A. Construction of Expression Vector pCZR225 that Expresseshuzcytor11/MBP-6H Fusion Polypeptide

An expression plasmid containing a polynucleotide encoding a zcytor11soluble receptor fused C-terminally to maltose binding protein (MBP) isconstructed via homologous recombination. The fusion polypeptidecontains an N-terminal approximately 388 amino acid MBP portion fused tothe zcytor11 soluble receptor (SEQ ID NO:3). A fragment of zcytor11 cDNA(SEQ ID NO:1) is isolated using PCR as described herein. Two primers areused in the production of the zcytor11 fragment in a standard PCRreaction: (1) one containing about 40 bp of the vector flanking sequenceand about 25 bp corresponding to the amino terminus of the zcytor11, and(2) another containing about 40 bp of the 3′ end corresponding to theflanking vector sequence and about 25 bp corresponding to the carboxylterminus of the zcytor11. Two μl of the 100 μl PCR reaction is run on a1.0% agarose gel with 1×TBE buffer for analysis, and the expectedapproximately fragment is seen. The remaining PCR reaction is combinedwith the second PCR tube and precipitated with 400 μl of absoluteethanol. The precipitated DNA used for recombining into the Sma1 cutrecipient vector pTAP98 to produce the construct encoding theMBP-zcytor11 fusion, as described below.

Plasmid pTAP98 is derived from the plasmids pRS316 and pMAL-c2. Theplasmid pRS316 is a Saccharomyces cerevisiae shuttle vector (Hieter P.and Sikorski, R., Genetics 122:19–27, 1989). pMAL-C2 (NEB) is an E. coliexpression plasmid. It carries the tac promoter driving MalE (geneencoding MBP) followed by a His tag, a thrombin cleavage site, a cloningsite, and the rrnB terminator. The vector pTAP98 is constructed usingyeast homologous recombination. 100 ng of EcoR1 cut pMAL-c2 isrecombined with 1 μg Pvu1 cut pRS316, 1 μg linker, and 1 μg Sca1/EcoR1cut pRS316 are combined in a PCR reaction. PCR products are concentratedvia 100% ethanol precipitation.

Competent yeast cells (S. cerevisiae) are combined with about 10 μl of amixture containing approximately 1 μg of the zcytor11 receptor PCRproduct above, and 100 ng of SmaI digested pTAP98 vector, andelectroporated using standard methods and plated onto URA-D plates andincubated at 30° C.

After about 48 hours, the Ura+ yeast transformants from a single plateare picked, DNA isolated, and transformed into electrocompetent E. colicells (e.g., MC1061, Casadaban et. al. J. Mol. Biol. 138, 179–207), andplated on MM/CA +AMP 100 mg/L plates (Pryor and Leiting, ProteinExression and Pruification 10:309–319, 1997).using standard procedures.Cells are grown in MM/CA with 100 μg/ml Ampicillin for two hours,shaking, at 37° C. 1 ml of the culture is induced with 1 mM IPTG. 2–4hours later the 250 μl of each culture is mixed with 250 μl acid washedglass beads and 250 μl Thomer buffer with 5% βME and dye (8M urea, 100mM Tris pH7.0, 10% glycerol, 2 mM EDTA, 5% SDS). Samples are vortexedfor one minute and heated to 65° C. for 10 minutes. 20 μl are loaded perlane on a 4%–12% PAGE gel (NOVEX). Gels are run in 1×MES buffer. Thepositive clones are designated pCZR225 and subjected to sequenceanalysis.

One microliter of sequencing DNA is used to transform strain BL21. Thecells are electropulsed at 2.0 kV, 25 μF and 400 ohms. Followingelectroporation, 0.6 ml MM/CA with 100 mg/L Ampicillin. Cells are grownin MM/CA and induced with ITPG as described above., The positive clonesare used to grow up for protein purification of the huzcytor11/MBP-6Hfusion protein using standard techniques.

EXAMPLE 4 Zcytor11 Soluble Receptor Polyclonal Antibodies

Polyclonal antibodies are prepared by immunizing female New Zealandwhite rabbits with the purified huzcytor11/MBP-6H polypeptide (Example3), or the purified recombinant zcytor11CEE soluble receptor (Example1). The rabbits are each given an initial intraperitoneal (IP) injectionof 200 mg of purified protein in Complete Freund's Adjuvant (Pierce,Rockford, Ill.) followed by booster IP injections of 100 mg purifiedprotein in Incomplete Freund's Adjuvant every three weeks. Seven to tendays after the administration of the third booster injection, theanimals are bled and the serum is collected. The rabbits are thenboosted and bled every three weeks.

The zcytor11-specific polyclonal antibodies are affinity purified fromthe rabbit serum using an CNBr-SEPHAROSE 4B protein column (PharmaciaLKB) that is prepared using about 10 mg of the purifiedhuzcytor11/MBP-6H polypeptide per gram CNBr-SEPHAROSE, followed by 20×dialysis in PBS overnight. Zcytor11-specific antibodies arecharacterized by an ELISA titer check using 1 mg/ml of the appropriateprotein antigen as an antibody target. The lower limit of detection(LLD) of the rabbit anti-zcytor11 affinity purified antibodies isdetermined using standard methods.

EXAMPLE 5 Zcytor11 Receptor Monoclonal Antibodies

Zcytor11 soluble receptor Monoclonal antibodies are prepared byimmunizing male BalbC mice (Harlan Sprague Dawley, Indianapolis, Ind.)with the purified recombinant soluble zcytor11 proteins describedherein. The mice are each given an initial intraperitoneal (IP)injection of 20 mg of purified protein in Complete Freund's Adjuvant(Pierce, Rockford, Ill.) followed by booster IP injections of 10 mgpurified protein in Incomplete Freund's Adjuvant every two weeks. Sevento ten days after the administration of the third booster injection, theanimals are bled and the serum is collected, and antibody titerassessed.

Splenocytes are harvested from high-titer mice and fused to murine SP2/0myeloma cells using PEG 1500 (Boerhinger Mannheim, UK) in two separatefusion procedures using a 4:1 fusion ratio of splenocytes to myelomacells (Antibodies: A Laboratory Manual, E. Harlow and D. Lane, ColdSpring Harbor Press). Following 10 days growth post-fusion, specificantibody-producing hybridomas are identified by ELISA using purifiedrecombinant zcytor11 soluble receptor protein (Example 6C) as anantibody target and by FACS using Baf3 cells expressing the zcytor11sequence (Example 8) as an antibody target. The resulting hybridomaspositive by both methods are cloned three times by limiting dilution.

EXAMPLE 6 Assessing Zcytor11 Receptor Heterodimerization Using ORIGENAssay

Soluble zcytor11 receptor zcytor11CFLAG (Example 1), or gp130 (Hibi, M.et al., Cell 63:1149–1157, 1990) are biotinylated by reaction with afive-fold molar excess of sulfo-NHS-LC-Biotin (Pierce, Inc., Rockford,Ill.) according to the manufacturer's protocol. Soluble zcytor11receptor and another soluble receptor subunit, for example, solubleIL-10R (sIL-10R) or CRF2-4 receptor (CRF2-4) (R&D Systems, Minneapolis,Minn.), or soluble zcytor11 receptor (U.S. Pat. No. 5,965,704) arelabeled with a five fold molar excess of Ru-BPY-NHS (Igen, Inc.,Gaithersburg, Md.) according to manufacturer's protocol. Thebiotinylated and Ru-BPY-NHS-labeled forms of the soluble zcytor11receptor can be respectively designated Bio-zcytor11 receptor andRu-zcytor11; the biotinylated and Ru-BPY-NHS-labeled forms of the othersoluble receptor subunit can be similarly designated. Assays can becarried out using conditioned media from cells expressing a ligand, suchas IL-TIF, that binds zcytor11 heterodimeric receptors, or usingpurified IL-TIF.

For initial receptor binding characterization a panel of cytokines orconditioned medium are tested to determine whether they can mediatehomodimerization of zcytor11 receptor and if they can mediate theheterodimerization of zcytor11 receptor with the soluble receptorsubunits described above. To do this, 50 □l of conditioned media orTBS-B containing purified cytokine, is combined with 50 □l of TBS-B (20mM Tris, 150 mM NaCl, 1 mg/ml BSA, pH 7.2) containing e.g., 400 ng/ml ofRu-zcytor11 receptor and Bio-zcytor11, or 400 ng/ml of Ru-zcytor11receptor and e.g., Bio-gp130, or 400 ng/ml of e.g., Ru-CRF2-4 andBio-zcytor11. Following incubation for one hour at room temperature, 30μg of streptavidin coated, 2.8 mm magnetic beads (Dynal, Inc., Oslo,Norway) are added and the reaction incubated an additional hour at roomtemperature. 200 μl ORIGEN assay buffer (Igen, Inc., Gaithersburg, Md.)is then added and the extent of receptor association measured using anM8 ORIGEN analyzer (Igen, Inc.).

EXAMPLE 7 Construct for Generating a zcytor11 Receptor Heterodimer

A vector expressing a secreted human zcytor11 heterodimer wasconstructed. In this construct, the extracellular cytokine-bindingdomain of zcytor11 was fused to the heavy chain of IgG gamma 1 (IgGγ1)with a Glu-Glu tag (SEQ ID NO:4) at the C-terminus, while theextracellular portion of the heteromeric cytokine receptor subunit(e.g., an CRF2-4, IL-9, IL-10 IL-4 receptor component) was fused to theheavy chain of IgG gamma 1 (IgGγ1) with a His tag at the C-terminus.

A. Construction of IgG Gamma 16-His and IgG Gamma 1 Glu-Glu FusionVectors

The heavy chain of IgGγ1 with a 6-His c-terminal tag (SEQ ID NO:13) wascloned into the pZP-9 mammalian expression vector (ATCC Deposit No.98668) such that any desired cytokine receptor extracellular domainhaving a 5′ EcoRI and 3′ BamHI site can be cloned in, resulting in anN-terminal extracellular domain-C-terminal IgGγ1 fusion. The IgGγ1fragment used in this construct was made by using PCR to isolate theIgGγ1 uaing oligonucleotide primers ZC29,239 (SEQ ID NO:14) and ZC29,232(SEQ ID NO:15). PCR products were purified using methods describedherein and digested with XhoI and BamHI (Boerhinger-Mannheim) andsubsequently gel purified. The extracellular portion of CRF2-4 (SEQ IDNO:18) was amplified using PCR, using oligonucleotide primers ZC39,319(SEQ ID NO:16) and ZC39,325 (SEQ ID NO:17). PCR products were purifiedusing methods described herein and digested with EcoRI and BamHI(Boerhinger-Mannheim) and subsequently gel purified. The BamHI/XhoIIgGγ1 fragment and EcoRI/BamHI CRF2-4 fragment derived above were thenligated together into pZP-9 previously digested with EcoRI and XhoI toderive a construct that had the extracellular portion of CRF2-4extracellular cytokine binding domain fused to IgGγ1 with a 6-HIS tag atthe c-terminus. This construct was subsequently modified to introduce athrombin cleavage site 3′ of CRF2-4 and 5′ of the 6-HIS tag. This wasdone by using the above construct as template in PCR witholigonucleotide primers ZC38,981 (SEQ ID NO:20) and ZC39,042 (SEQ IDNO:21). PCR products were purfied using methods described herein anddigested with SacII and XhoI. This SacII/XhoI fragment was ligated intothe construction described above that had been previously digested withSacII and XhoI. The polynucleotide sequence of the CRF2-4 extracellularcytokine binding domain fused to IgGγ1 with a 6-HIS tag is shown in SEQID NO:22 and the corresponding polypeptide sequence is shown in SEQ IDNO:23.

The heavy chain of IgGγ1 with a Glu-Glu c-terminal tag (SEQ ID NO:4) wascloned into the Zem228R mammalian expression vector (ATCC deposit No.69446) such that any desired cytokine receptor extracellular domainhaving a 5′ EcoRI site and a 3′ BamHI site can be cloned in resulting ina N-terminal cytokine extracellular domain-C-terminal IgGγ1 fusion. TheIgGγ1 fragment used in this construct was made by using PCR to isolatethe IgGγ1 sequence using oligonucleotide primers ZC29238 (SEQ ID NO:24)and ZC29231 (SEQ ID NO:25). PCR products were purified using methodsdescribed herein and digested with XhoI and EcoRI (Boerhinger-Mannheim)and subsequently gel purified. The extracellular portion of hzcytor11(SEQ ID NO:1) was amplified using PCR using oligonucleotides ZC39335(SEQ ID NO:26) and ZC28981 (SEQ ID NO:27). PCR products were purifiedusing methods described herein and digested with EcoRI and BamHI(Boerhinger-Mannheim) and subsequently gel purified. The BamHI/XhoIIgGγ1 fragment and EcoRI/BamHI hzcytor11 fragments derived above werethen ligated together into Zem228R previously digested with EcoRI andXhoI to derive a construct that had the extracellular domain ofhzcytor11 fused to IgGγ1 with a Glu-Glu epitope tag at the C-terminus.This construct was subsequently modified to introduce a thrombincleavage site 3′ of CRF2-4 and 5′ of the 6-HIS tag. This was done byusing the above construct as template in PCR with oligonucleotideprimers ZC38981 (SEQ ID NO:27) and ZC39043 (SEQ ID NO:28). PCR productswere purfied using methods described herein and digested with SacIIl andXhoI. This SacII/XhoI fragment was ligated into the constructiondescribed above that had been previously digested with SacII and XhoI.The polynucleotide sequence of the hzcytor11 extracellular cytokinebinding domain fused to IgGγ1 with a Glu-Glu tag is shown in SEQ IDNO:29 and the corresponding polypeptide sequence is shown in SEQ IDNO:30.

B. Co-expression of the zcytor11 and Heterodimeric Cytokine ReceptorSubunit Extracellular Domain

16 μg of each of vectors above, were co-transfected into mammaliancells, e.g., BHK-570 cells (ATCC No. CRL-10314) using LipofectaminePlus™reagent (Gibco/BRL), as per manufacturer's instructions. The transfectedcells were selected for 10 days in DMEM+5% FBS (Gibco/BRL) containing 1μM of methotrexate (MTX) (Sigma, St. Louis, Mo.) and 0.5 mg/ml G418(Gibco/BRL) for 10 days. The resulting pool of transfectants wasselected again in 10 μm of MTX and 0.5 mg/ml G418 for 10 days.

The resulting pool of doubly selected cells was used to generatezcytor11/CRF2-4 soluble receptor protein. Three Factories (Nunc,Denmark) of this pool were used to generate 10 L of serum freeconditioned medium. This conditioned media was passed over a nickelcolumn followed by a Glu-Glu column to purify heterodimers away fromhomodimers.

EXAMPLE 8 Determination of Receptor Subunits that Heterodimerize orMultimerize with zcytor11 Receptor

Using standard methods described herein, The BaF3/MPL-zcytor11 chimeracells are transfected with an additional heterodimeric cytokine receptorsubunit serve as a bioassay cell line to measure signal transductionresponse of heterodimeric zcytor11 receptor complexes to the luciferasereporter in the presence of TPO. In the presence of TPO, theBaF3/MPL-zcytor11 cells do not signal, suggesting that zcytor11 receptormust heterodimerize to signal. Transfection of the BaF3/MPL-zcytor11cell line with and additional MPL-class I cytokine receptor fusion thatsignals in the presence of the TPO ligand, determines whichheterodimeric cytokine receptor subunits are required for zcytor11receptor signaling. Use of MPL-receptor fusions for this purposealleviates the requirement for the presence of a natural ligand for thezcytor11 receptor.

MPL-class I cytokine receptor fusions are made as per Example 5 usingthe extracellular domain and transmembrane domains of the MPL receptorand the intracellular signaling domain of the desired class I cytokinereceptor. The BaF3/MPL-zcytor11 bioassay cell line co-transfected withan individual MPL-class I cytokine receptor fusions as per Example 6 toform a BaF3/MPL-zcytor11/MPL-class I cytokine receptor cell line.Receptor complexes include but are not limited to zcytor11 receptor incombination with an MPL-cytokine receptor fusion comprising one or moreof e.g., a CRF2-4, IL-9, IL-10 IL-4 receptor component. Each independentreceptor complex cell line is then assayed in the presence of TPO andproliferation measured using routine methods (e.g., Alamar Blue assay).The BaF3/MPL-zcytor11 bioassay cell line serves as a control for thebackground luciferase activity, and is thus used as a baseline tocompare signaling by the various receptor complex combinations. Inaddition, a BaF3/MPL-class I cytokine receptor cell line can beconstructed to control for MPL-class I cytokine receptorhomodimerization effects for those class I cytokine receptors known tosignal upon homodimerization. The TPO in the presence of the correctreceptor complex, is expected to increase proliferation of theBaF3/MPL-zcytor11/MPL-class I cytokine receptor cell line approximately5 fold over background or greater in the presence of TPO.

Similar proliferation assays use full-length zcytor11 (SEQ ID NO:2) toscreen for additional non-zcytor11 subunits that signal heterodimericand multimeric complexes. Cells expressing full-length zcytor11 (SEQ IDNO:2) are transfected with a non-zcytor11 subunit and assayed forproliferation in the presence of IL-TIF ligand. Cells expressing thecomponents of zcytor11 heterodimeric and multimeric receptors shouldproliferate in the presence of IL-TIF.

EXAMPLE 9 Reconstitution of zcytor11 Receptor in vitro

To identify components involved in the zcytor11-signaling complex,receptor reconstitution studies are performed as follows. BHK 570 cells(ATCC No. CRL-10314) transfected, using standard methods describedherein, with a luciferase reporter mammalian expression vector plasmidserve as a bioassay cell line to measure signal transduction responsefrom a transfected zcytor11 receptor complex to the luciferase reporterin the presence of IL-TIF. BHK cells do not endogenously express thezcytor11 receptor. An exemplary luciferase reporter mammalian expressionvector is the KZ134 plasmid which was constructed with complementaryoligonucleotides that contain STAT transcription factor binding elementsfrom 4 genes. A modified c-fos Sis inducible element (m67SIE, or hSIE)(Sadowski, H. et al., Science 261:1739–1744, 1993), the p21 SIE1 fromthe p21 WAF1 gene (Chin, Y. et al., Science 272:719–722, 1996), themammary gland response element of the β-casein gene (Schmitt-Ney, M. etal., Mol. Cell. Biol. 11:3745–3755, 1991), and a STAT inducible elementof the Fcg RI gene, (Seidel, H. et al., Proc. Natl. Acad. Sci.92:3041–3045, 1995). These oligonucleotides contain Asp718-XhoIcompatible ends and were ligated, using standard methods, into arecipient firefly luciferase reporter vector with a c-fos promoter(Poulsen, L. K. et al., J. Biol. Chem. 273:6229–6232, 1998) digestedwith the same enzymes and containing a neomycin selectable marker. TheKZ134 plasmid is used to stably transfect BHK, or BaF3 cells, usingstandard transfection and selection methods, to make a BHK/KZ134 orBaF3/KZ134 cell line respectively.

The bioassay cell line is transfected with zcytor11 receptor alone, orco-transfected with zcytor11 receptor along with one of a variety ofother known receptor subunits. Receptor complexes include but are notlimited to zcytor11 receptor only, various combinations of zcytor11receptor with one or more of the CRF2-4, IL-9, IL-10 IL-4 receptorcomponents, class II cytokine receptor subunits, or the IL-2 receptorcomponents (IL-2Rα, IL-2Rβ, IL-2Rγ), zcytor11 receptor with one or moreof the IL-4/IL-13 receptor family receptor components (IL-4Rα, IL-13Rα,IL-13Rα′), as well as other Interleukin receptors (e.g., IL-15 Rα,IL-7Rα, IL-9Rα, IL-21R (zcytor11)). Each independent receptor complexcell line is then assayed in the presence of cytokine-conditioned mediaor purified cytokines and luciferase activity measured using routinemethods. The untransfected bioassay cell line serves as a control forthe background luciferase activity, and is thus used as a baseline tocompare signaling by the various receptor complex combinations. Theconditioned medium or cytokine that binds the zyctorlo receptor in thepresence of the correct receptor complex, is expected to give aluciferase readout of approximately 5 fold over background or greater.

As an alternative, a similar assay can be performed wherein theBaf3/zcytor11-mpl and Baf3/zcytor11 cell lines are co-transfected asdescribed above and proliferation measured.

EXAMPLE 10 Construct for Generating CEE-tagged IL-TIF

Oligonucleotides were designed to generate a PCR fragment containing theKozak sequence and the coding region for IL-TIF, without its stop codon.These oligonucleotides were designed with a KpnI site at the 5′ end anda BamHI site at the 3′ end to facilitate cloning into pHZ200-CEE, ourstandard vector for mammalian expression of C-terminal Glu-Glu tagged(SEQ ID NO:4) proteins. The pHZ200 vector contains an MT-1 promoter.

PCR reactions were carried out using Turbo Pfu polymerase (Stratagene)to amplify a IL-TIF cDNA fragment. About 20 ng human IL-TIFpolynucleotide template (SEQ ID NO:7), and oligonucleotides ZC28590 (SEQID NO:9) and ZC28580 (SEQ ID NO:10) were used in the PCR reaction. PCRreaction conditions were as follows: 95° C. for 5 minutes; 30 cycles of95° C. for 60 seconds, 55° C. for 60 seconds, and 72° C. for 60 seconds;and 72° C. for 10 minutes; followed by a 4° C. hold. PCR products wereseparated by agarose gel electrophoresis and purified using a QiaQuick™(Qiagen) gel extraction kit. The isolated, approximately 600 bp, DNAfragment was digested with KpnI and BamHI (Boerhinger-Mannheim), gelpurified as above and ligated into pHZ200-CEE that was previouslydigested with KpnI and BamHI.

About one microliter of the ligation reaction was electroporated intoDH10B ElectroMax™ competent cells (GIBCO BRL, Gaithersburg, Md.)according to manufacturer's direction and plated onto LB platescontaining 100 μg/ml ampicillin, and incubated overnight. Colonies werepicked and screened by PCR using oligonucleotides ZC28590 (SEQ ID NO:9)and ZC28580 (SEQ ID NO:10), with PCR conditions as described above.Clones containing inserts were then sequenced to confirm error-freeIL-TIF inserts. Maxipreps of the correct pHZ200-IL-TIF-CEE construct, asverified by sequence analysis, were performed.

EXAMPLE 11 Transfection and Expression of IL-TIF Polypeptides

BHK 570 cells (ATCC No. CRL-10314), were plated at about 1.2×10⁶cells/well (6-well plate) in 800 μl of serum free (SF) DMEM media (DMEM,Gibco/BRL High Glucose) (Gibco BRL, Gaithersburg, Md.). The cells weretransfected with an expression plasmid containing IL-TIF-CEE describedabove (Example 10), using Lipofectin™ (Gibco BRL), in serum free (SF)DMEM according to manufacturer's instructions.

The cells were incubated at 37° C. for approximately five hours, thentransferred to separate 150 mm MAXI plates in a final volume of 30 mlDMEM/5% fetal bovine serum (FBS) (Hyclone, Logan, Utah). The plates wereincubated at 37° C., 5% CO₂, overnight and the DNA: Lipofectin™ mixturewas replaced with selection media (5% FBS/DMEM with 1 μM methotrexate(MTX)) the next day.

Approximately 10–12 days post-transfection, colonies were mechanicallypicked to 12-well plates in one ml of 5% FCS/DMEM with 5 μM MTX, thengrown to confluence. Positive expressing clonal colonies Conditionedmedia samples were then tested for expression levels via SDS-PAGE andWestern analysis. A high-expressing clone was picked and expanded forample generation of conditioned media for purification of the IL-TIF-CEEexpressed by the cells (Example 12).

EXAMPLE 12 Purification of IL-TIF-CEE Polypeptide from BHK 570 Cells

Unless otherwise noted, all operations were carried out at 4° C. Thefollowing procedure was used for purifying IL-TIF polypeptide containingC-terminal GluGlu (EE) tags (SEQ ID NO:4). Conditioned media from BHKcells expressing IL-TIF-CEE (Example 11) was concentrated with an AmiconS10Y3 spiral cartridge on a ProFlux A30. A Protease inhibitor solutionwas added to the concentrated conditioned media to final concentrationsof 2.5 mM ethylenediaminetetraacetic acid (EDTA, Sigma Chemical Co. St.Louis, Mo.), 0.003 mM leupeptin (Boehringer-Mannheim, Indianapolis,Ind.), 0.001 mM pepstatin (Boehringer-Mannheim) and 0.4 mM Pefabloc(Boehringer-Mannheim). Samples were removed for analysis and the bulkvolume was frozen at −80° C. until the purification was started. Totaltarget protein concentrations of the concentrated conditioned media weredetermined via SDS-PAGE and Western blot analysis with the anti-EE HRPconjugated antibody.

About 100 ml column of anti-EE G-Sepharose (prepared as described below)was poured in a Waters AP-5, 5 cm×10 cm glass column. The column wasflow packed and equilibrated on a BioCad Sprint (PerSeptive BioSystems,Framingham, Mass.) with phosphate buffered saline (PBS) pH 7.4. Theconcentrated conditioned media was thawed, 0.2 micron sterile filtered,pH adjusted to 7.4, then loaded on the column overnight with about 1ml/minute flow rate. The column was washed with 10 column volumes (CVs)of phosphate buffered saline (PBS, pH 7.4), then plug eluted with 200 mlof PBS (pH 6.0) containing 0.5 mg/ml EE peptide (Anaspec, San Jose,Calif.) at 5 ml/minute. The EE peptide used has the sequence EYMPME (SEQID NO:4). The column was washed for 10 CVs with PBS, then eluted with 5CVs of 0.2M glycine, pH 3.0. The pH of the glycine-eluted column wasadjusted to 7.0 with 2 CVs of 5×PBS, then equilibrated in PBS (pH 7.4).Five ml fractions were collected over the entire elution chromatographyand absorbance at 280 and 215 nM were monitored; the pass through andwash pools were also saved and analyzed. The EE-polypeptide elution peakfractions were analyzed for the target protein via SDS-PAGE Silverstaining and Western Blotting with the anti-EE HRP conjugated antibody.The polypeptide elution fractions of interest were pooled andconcentrated from 60 ml to 5.0 ml using a 10,000 Dalton molecular weightcutoff membrane spin concentrator (Millipore, Bedford, Mass.) accordingto the manufacturer's instructions.

To separate IL-TIF-CEE from other co-purifying proteins, theconcentrated polypeptide elution pooled fractions were subjected to aPOROS HQ-50 (strong anion exchange resin from PerSeptive BioSystems,Framingham, Mass.) at pH 8.0. A 1.0×6.0 cm column was poured and flowpacked on a BioCad Sprint. The column was counter ion charged thenequibrated in 20 mM TRIS pH 8.0 (Tris (Hydroxymethyl Aminomethane)). Thesample was diluted 1:13 (to reduce the ionic strength of PBS) thenloaded on the Poros HQ column at 5 ml/minute. The column was washed for10 CVs with 20 mM Tris pH 8.0 then eluted with a 40 CV gradient of 20 mMTris/1 M sodium chloride (NaCl) at 10 ml/minute. 1.5 ml fractions werecollected over the entire chromatography and absorbance at 280 and 215nM were monitored. The elution peak fractions were analyzed via SDS-PAGESilver staining. Fractions of interest were pooled and concentrated to1.5–2 ml using a 10,000 Dalton molecular weight cutoff membrane spinconcentrator (Millipore, Bedford, Mass.) according to the manufacturer'sinstructions.

To separate IL-TIF-CEE polypeptide from free EE peptide and anycontaminating co-purifying proteins, the pooled concentrated fractionswere subjected to size exclusion chromatography on a 1.5×90 cm SephadexS200 (Pharmacia, Piscataway, N.J.) column equilibrated and loaded in PBSat a flow rate of 1.0 ml/min using a BioCad Sprint. 1.5 ml fractionswere collected across the entire chromatography and the absorbance at280 and 215 nM were monitored. The peak fractions were characterized viaSDS-PAGE Silver staining, and only the most pure fractions were pooled.This material represented purified IL-TIF-CEE polypeptide.

This purified material was finally subjected to a 4 ml ActiClean Etox(Sterogene) column to remove any remaining endotoxins. The sample waspassed over the PBS equilibrated gravity column four times then thecolumn was washed with a single 3 ml volume of PBS, which was pooledwith the “cleaned” sample. The material was then 0.2 micron sterilefiltered and stored at −80° C. until it was aliquoted.

On Western blotted, Coomassie Blue and Silver stained SDS-PAGE gels, theIL-TIF-CEE polypeptide was one major band. The protein concentration ofthe purified material was performed by BCA analysis (Pierce, Rockford,Ill.) and the protein was aliquoted, and stored at −80° C. according tostandard procedures.

To prepare anti-EE Sepharose, a 100 ml bed volume of protein G-Sepharose(Pharmacia, Piscataway, N.J.) was washed 3 times with 100 ml of PBScontaining 0.02% sodium azide using a 500 ml Nalgene 0.45 micron filterunit. The gel was washed with 6.0 volumes of 200 mM triethanolamine, pH8.2 (TEA, Sigma, St. Louis, Mo.), and an equal volume of EE antibodysolution containing 900 mg of antibody was added. After an overnightincubation at 4° C., unbound antibody was removed by washing the resinwith 5 volumes of 200 mM TEA as described above. The resin wasresuspended in 2 volumes of TEA, transferred to a suitable container,and dimethylpimilimidate-2HCl (Pierce, Rockford, Ill.) dissolved in TEA,was added to a final concentration of 36 mg/ml of protein G-Sepharosegel. The gel was rocked at room temperature for 45 min and the liquidwas removed using the filter unit as described above. Nonspecific siteson the gel were then blocked by incubating for 10 min. at roomtemperature with 5 volumes of 20 mM ethanolamine in 200 mM TEA. The gelwas then washed with 5 volumes of PBS containing 0.02% sodium azide andstored in this solution at 4° C.

EXAMPLE 13 In vivo Affects of L-TIF Polypeptide

Mice (female, C57B1, 8 weeks old; Charles River Labs, Kingston, N.Y.)were divided into three groups. An adenovirus expressing an IL-TIFpolypeptide (SEQ ID NO:8) was previously made using standard methods. Onday 0, parental or IL-TIF adenovirus was administered to the first (n=8)and second (n=8) groups, respectively, via the tail vein, with eachmouse receiving a dose of ˜1×10¹¹ particles in ˜0.1 ml volume. The thirdgroup (n=8) received no treatment. On days 12, mice were weighed andblood was drawn from the mice. Samples were analyzed for complete bloodcount (CBC) and serum chemistry. Statistically significant elevations inneutrophil and platelet counts were detected in the blood samples fromthe IL-TIF adenovirus administered group relative to the parentaladenovirus treated group. Also, lymphocyte and red blood cell countswere significantly reduced from the IL-TIF adenovirus administered grouprelative to the parental adenovirus treated group. In addition, theIL-TIF adenovirus treated mice decreased in body weight, while parentaladenovirus treated mice gained weight. The SAA and globulin level wasincreased and glucose level was decreased. The adeno-zcyto18 micedisplayed wasting syndrome. In summary, zcyto18 causes acute phaseresponse (APR) that reflects the pro-inflammatory activity of TNF-α,IL-1, and gp130 cytokines.

The result suggested that IL-TIF is a pro-inflammatory factor that isinvolved in the immune and inflammatory response in vivo. The tissuedistribution of IL-TIF receptor (zcytor11) indicated that elevatedexpression of IL-TIF in circulation or specific tissues can lead tocertain acute/chronic inflammatory diseases, such as pancreatitis, IBD(Chron's disease, colitis), asthma, ESRD (end stage renal diseases),rheumatoid arthritis, psoriasis, and autoimmune diseases (GVHD, lupus,sepsis).

The results suggested that IL-TIF affects hematopoiesis, i.e., bloodcell formation in vivo. As such, IL-TIF could have biological activitieseffecting different blood stem cells, thus resulting increase ordecrease of certain differentiated blood cells in a specific lineage.For instance, IL-TIF appears to reduce lymphocytes, which is likely dueto inhibition of the committed progenitor cells that give rise tolymphoid cells. IL-TIF also decreases red blood cells. This findingagrees with the inhibitory effects of IL-TIF on the proliferation and/orgrowth of myeloid stem cells (Example 13), supporting the notion thatIL-TIF could play a role in anemia, infection, inflammation, and/orimmune diseases by influencing blood cells involved in these process.Antagonists against IL-TIF, such as antibodies or zcytor11 solublereceptors of the present invention, could be used as therapeuticreagents in these diseases.

Moreover, these experiments using IL-TIF adenovirus in mice suggest thatIL-TIF over-expression increases the level of neutrophils and plateletsin vivo. It is conceivable that there are other factors (such ascytokines and modifier genes) involved in the responses to IL-TIF in thewhole animal system. Nevertheless, these data strongly support theinvolvement of IL-TIF in hematopoiesis. Thus, IL-TIF and its receptorsare suitable reagents/targets for the diagnosis and treatment in varietyof disorders, such as inflammation, immune disorders, infection, anemia,hematopoietic and other cancers, and the like.

EXAMPLE 14 Identification of Cells Expressing zcytor11 Using in situHybridization

Specific human tissues were isolated and screened for zcytor11expression by in situ hybridization. Various human tissues prepared,sectioned and subjected to in situ hybridization included appendix,brain, cartilage, colon, intestine, kidney, liver, lung, lymph node,lymphoma, ovary, pancreas, placenta, prostate, skin, spleen, and thymus.The tissues were fixed in 10% buffered formalin and blocked in paraffinusing standard techniques. Tissues were sectioned at 4 to 8 microns.Tissues were prepared using a standard protocol (“Development ofnon-isotopic in situ hybridization” at The Laboratory of ExperimentalPathology (LEP), NIEHS, Research Triangle Park, N.C.; web addresshttp://dir.niehs.nih.gov/dirlep/ish.html). Briefly, tissue sections weredeparaffinized with HistoClear (National Diagnostics, Atlanta, Ga.) andthen dehydrated with ethanol. Next they were digested with Proteinase K(50 μg/ml) (Boehringer Diagnostics, Indianapolis, Ind.) at 37° C. for 2to 7 minutes. This step was followed by acetylation and re-hydration ofthe tissues.

One in situ probe was designed against the human zcytor11 sequence(nucleotide 234–1105 in SEQ ID NO:1), and isolated from a plasmidcontaining SEQ ID NO:11 using standard methods. T7 RNA polymerase wasused to generate an antisense probe. The probe was labeled withdigoxigenin (Boehringer) using an In Vitro transcription System(Promega, Madison, Wis.) as per manufacturer's instruction.

In situ hybridization was performed with a digoxigenin-labeled zcytor11probe (above). The probe was added to the slides at a concentration of 1to 5 pmol/ml for 12 to 16 hours at 60° C. Slides were subsequentlywashed in 2×SSC and 0.1×SSC at 55° C. The signals were amplified usingtyramide signal amplification (TSA) (TSA, in situ indirect kit; NEN) andvisualized with Vector Red substrate kit (Vector Lab) as permanufacturer's instructions. The slides were then counter-stained withhematoxylin (Vector Laboratories, Burlingame, Calif.).

Signals were observed in several tissues tested: The lymph node thatcontains cells in the paracortex of nodules was strongly positive. Inlymphoma samples, there is little to no signal in the samples tested. Inspleen, positive signals were seen in scattered mononuclear cells at theperiphery of follicles were positive. In thymus, positive signals wereseen in scattered mononuclear cells in both cortex and medulla waspositive. In fetal liver, a strong signal was observed in a mixedpopulation of mononuclear cells in sinusoid spaces. Some circulatingmononuclear cells were also positive. Hepatocytes were negative. In theinflamed appendix, mononuclear cells in Peyer's patch and infiltrationsites were positive. In intestine, cells in laminar propria and Peyer'spatches were strongly positive. Ganglia nerve cells in the muscles werepositive. In normal lung, zcytor11 was expressed in alveolar epitheliumand mononuclear cells in interstitial tissue and circulation. In thelung carcinoma tissue, a weak signal was observed in carcinoma cells andmononuclear cells in peripheral of carcinoma sites. In ovary carcinoma,epithelium cells were strongly positive. Some interstitial cells, mostlikely the mononuclear cells, were also positive. There was no signalobserved in the normal ovary. In kidney, podocytes and simple epithelialcells in the parietal layer of Bowman's capsules in renal corpuscleswere positive. Cuboidal epithelial cells of distal convoluted tubuleswere also positive. In both normal and pancreatitis pancreas samples,acinar cells and some mononuclear cells in the mesentery were positive.There may be also weak signal in a subset of cells in islets ofpancreas. In the early term (8 weeks) placenta, signal was observed introphoblasts. In skin, strong signal was observed in the keratinocytesand mononuclear cells in the inflamed infiltrates in the superficialdermis. In brain, majority of neurons in temporal lobe were positive,however, the frontal lobe appears to be negative. In articularcartilage, chondrocytes were positive. Other tissues tested includingnormal ovary, skin melanoma, prostate carcinoma and BPH were negative.

In summary, the in situ data was consistent with expression datadescribed above for the zcytor11. Zcytor11 expression was observedpredominately and consistently expressed by a mixed population ofmononuclear cells. A subset of epithelium was also positive. Theseresults confirmed the presence of zcytor11 expression in immune cellsand point toward a role in inflammation, autoimmune disease, or otherimmune function, for example, in binding pro-inflammatory cytokines,including but not limited to IL-TIF. Moreover, detection of zcytor11expression can be used for example as a marker for mononuclear cells inhistologic samples.

Zcytor11 is expressed in mononuclear cells, including normal tissues(lymph nodes, spleen, thymus, pancreas, kidney, liver and lung), andabnormal tissues (inflamed appendix, lung carcinoma, ovary carcinoma,pancreatitis, inflamed skin, and prostate carcinoma). It is notable thatplasma cells in the lymph node, intestine, and lung carcinoma arepositive for zcytor11. Plasma cells are immunologically activatedlymphocytes responsible for antibody synthesis. In addition, IL-TIF isexpressed in activated T cells, and the expression of zcytor11 isdetected only in resting (but not in activated) CD19+ cells (Example13). Thus, zcytor11 can be used as a marker for or as a target inisolating certain lymphocytes, such as mononuclear leucocytes andlimited type of activated leucocytes, such as resting CD19+.

Furthermore, the presence of zcytor11 expression in immune cells such asCD8+ T cell and CD19+ B cells showed that zcytor11 may be involved inthe body's immune defensive reactions against foreign invaders: such asmicroorganisms and cell debris, and could play a role in immuneresponses during inflammation and cancer formation. The activation ofzcytor11 receptor may cause autoimmune and inflammatory diseases such asGVHD, sepsis and lupus.

Moreover, as discussed herein, epithelium form several tissues waspositive for zcytor11 expression, such as skin, kidney, gut, hepatocytes(endoderm-derived epithelia), lung alveolar epithelium (endoderm-derivedepithelia), and ovary carcinoma epithelium (mesoderm-derivedepithelium). The inflammatory response in these tissues may causeacute/chronic inflammatory diseases, such as psoriasis (skin), end-stagerenal disease ESRD (kidney), IBD (Chron's disease, colitis) (gut), andasthma/respiratory allergy/chronic bronchitis (lung). The epitheliumexpression of zcytor11 could be altered in inflammatory responses and/orcancerous states in liver and lung. Thus, ligand for zcytor11, such asIL-TIF, or a receptor-binding fragment thereof, could be used as markerto monitor changes in these tissues as a result of inflammation orcancer. Moreover, analysis of zcytor11 in situ expression showed thatnormal ovary epithelium is negative for zcytor11 expression, while it isstrongly positive in ovary carcinoma epithelium providing furtherevidence that IL-TIF polypeptides, or a receptor-binding fragmentthereof, can be used as a diagnostic marker and/or therapeutic targetfor the diagnosis and treatment of ovarian cancers, and ovary carcinoma,as described herein.

Zcytor11 was also detected in other tissues, such as acinar cells inpancreas (normal and pancreatitis tissues), trophoblasts in placenta(ectoderm-derived), chondrocytes in cartilage (mesoderm-derived), andganglia cells in intestine (ectoderm-derived). As such, zcytor11 may beinvolved in differentiation and/or normal functions of correspondingcells in these organs. As such, potential utilities of zcytor11 includemaintenance of normal metabolism and pregnancy, boneformation/homeostasis, and physiological function of intestine, and thelike. Moreover, the up-regulation of IL-TIF may potentially cause theinflammatory response in those tissues that lead to certain inflammatorydiseases such as pancreatitis, rheumatoid arthritis, IBD (colitis andChron's disease).

EXAMPLE 15 Human zcytor11 Tissue Distribution in Tissue Panels UsingNorthern Blot and PCR

A. Human zcytor11 Tissue Distribution in Tissue Panels Using PCR

A panel of cDNAs from human tissues was screened for zcytor11 expressionusing PCR. The panel was made in-house and contained 94 marathon cDNAand cDNA samples from various normal and cancerous human tissues andcell lines are shown in Table 4 below. Aside from the PCR reaction, themethod used was as shown in Example 12. The PCR reactions were set upusing oligos ZC14,666 (SEQ ID NO: 11) and ZC14,742 (SEQ ID NO:12),Advantage 2 cDNA polymerase mix (Clontech, Palo Alto, Calif.), andRediload dye (Research Genetics, Inc., Huntsville, Ala.). Theamplification was carried out as follows: 1 cycle at 94° C. for 2minutes, 40 cycles of 94° C. for 15 seconds, 51° C. for 30 seconds and72° C. for 30 seconds, followed by 1 cycle at 72° C. for 7 minutes. Thecorrect predicted DNA fragment size was observed in bladder, brain,cervix, colon, fetal brain, fetal heart, fetal kidney, fetal liver,fetal lung, fetal skin, heart, kidney, liver, lung, melanoma, ovary,pancreas, placenta, prostate, rectum, salivary gland, small intestine,testis, thymus, trachea, spinal cord, thyroid, lung tumor, ovariantumor, rectal tumor, and stomach tumor. Zcytor11 expression was notobserved in the other tissues and cell lines tested in this panel.

A commercial 1st strand cDNA panel (Human Blood Fractions MTC Panel,Clontech, Palo Alto, Calif.) was also assayed as above. The panelcontained the following samples: mononuclear cells, activatedmononuclear cells, resting CD4+ cells, activated CD4+ cells, restingCD8+ cells, activated CD8+ cells, resting CD14+ cells, resting CD19+cells and activated CD19+ cells. All samples except activated CD8+ andActivated CD19+ showed expression of zcytor11.

TABLE 4 Tissue # samples Tissue # samples adrenal gland 1 bladder 1 bonemarrow 3 brain 2 cervix 1 colon 1 fetal brain 3 fetal heart 2 fetalkidney 1 fetal liver 2 fetal lung 1 fetal skin 1 heart 2 fetal muscle 1kidney 2 liver 1 lung 1 lymph node 1 mammary gland 1 melanoma 1 ovary 1pancreas 1 pituitary 2 placenta 3 prostate 3 rectum 1 salivary gland 2skeletal muscle 1 small intestine 1 spinal cord 2 spleen 1 uterus 1stomach 1 adipocyte library 1 testis 5 islet 1 thymus 1 prostate SMC 1thyroid 2 RPMI 1788 1 trachea 1 WI38 1 esophageal tumor 1 lung tumor 1liver tumor 1 ovarian tumor 1 rectal tumor 1 stomach tumor 1 uterinetumor 2 CD3+ library 1 HaCAT library 1 HPV library 1 HPVS library 1 MG63library 1 K562 1B. Tissue Distribution of Zcytor11 in Human Cell Line and Tissue PanelsUsing RT-PCR

A panel of RNAs from human cell lines was screened for zcytor11expression using RT-PCR. The panels were made in house and contained 84RNAs from various normal and cancerous human tissues and cell lines asshown in Tables 5–8 below. The RNAs were made from in house or purchasedtissues and cell lines using the RNAeasy Midi or Mini Kit (Qiagen,Valencia, Calif.). The panel was set up in a 96-well format with 100 ngsof RNA per sample. The RT-PCR reactions were set up using oligosZC14,666 (SEQ ID NO:11) and ZC14,742 (SEQ ID NO:12), Rediload dye andSUPERSCRIPT One Step RT-PCR System (Life Technologies, Gaithersburg,Md.). The amplification was carried out as follows: one cycle at 50° for30 minutes followed by 45 cycles of 94°, 15 seconds; 52°, 30 seconds;72°, 30 seconds; then ended with a final extension at 72° for 7 minutes.8 to 10 uls of the PCR reaction product was subjected to standardAgarose gel electrophoresis using a 4% agarose gel. The correctpredicted cDNA fragment size was observed in adrenal gland, bladder,breast, bronchus, normal colon, colon cancer, duodenum, endometrium,esophagus, gastic cancer, gastro-esophageal cancer, heart ventricle,iluem, normal kidney, kidney cancer, liver, lung, lymph node, pancreas,parotid, skin, small bowel, stomach, thyroid, and uterus. Cell linesshowing expression of zcytor11 were A-431, differentiated CaCO2, DLD-1,HBL-100, HCT-15, HepG2, HepG2+IL6, HuH7, and NHEK #1-4. Zcytor11expression was not observed in the other tissues and cell lines testedin this panel. The expression pattern of zcytor11 shows expression inspecific tissues and tissue-specific tumors. One of skill in the artwould recognize that the polynucleotides, polypeptides, antibodies, andbinding partners of the present invention can be used as a diagnostic todetect cancer, or cancer tissue in a biopsy, tissue, or histologicsample, particularly in tissues where zcytor11 is expressed. Suchdiagnostic uses for the molecules of the present invention are known inthe art and described herein.

In addition, because the expression pattern of zcytor11, one of IL-TIF'sreceptors, shows expression in certain specific tissues, bindingpartners including the natural ligand, IL-TIF, can also be used as adiagnostic to detect specific tissues (normal or abnormal), cancer, orcancer tissue in a biopsy, tissue, or histologic sample, particularly intissues where IL-TIF receptors are expressed. IL-TIF can also be used totarget other tissues wherein its receptors, e.g., zcytor11 and CRF2-4,are expressed. Moreover, such binding partners could be conjugated tochemotherapeutic agents, toxic moieties and the like to target therapyto the site of a tumor or diseased tissue. Such diagnostic and targetedtherapy uses are known in the art and described herein.

The expression patterns of zcytor11 (above) indicated target tissues andcell types for the action of IL-TIF, and hence IL-TIF antagonists, suchas the soluble zcytor11 receptors of the present invention. The zcytor11is generally expressed in three physiologic systems: digestive system,female reproductive system, and immune system. Moreover, the expressionpattern of the receptor (zcytor11) indicated that an IL-TIF antagonistthe soluble zcytor11 receptors of the present invention would havetherapeutic application for human disease in two areas: inflammation(e.g., IBD, Chron's disease, pancreatitis) and cancer (e.g., ovary,colon). That is, the polynucleotides, polypeptides and antibodies of thepresent invention can be used to antagonize the inflammatory, and othercytokine-induced effects of IL-TIF interaction with the cells expressingthe zcytor11 receptor.

Moreover, the expression of zcytor11 appeared to be downregulated orabsent in an ulcerative colitis tissue, HepG2 liver cell line induced byIL-6, activated CD8+ T-cells and CD19+ B-cells. These RT-PCR experimentsdemonstrate that CD19+ peripheral blood cells, B lymphocytes, expressreceptors for IL-TIF, namely zcytoR11. The soluble zcytor11 receptors ofthe present invention would act as an antagonist to neutralize theeffects of IL-TIF on B cells. This would be beneficial in diseases whereB cells are the key players: Autoimmune diseases including systemiclupus erythmatosus (SLE), myasthenia gravis, immune complex disease, andB-cell cancers that are exacerbated by IL-TIF. Also autoimmune diseaseswhere B cells contribute to the disease pathology would be targets forzcytor11 soluble receptor therapy: Multiple sclerosis, inflammatorybowel disease (IBD) and rheumatoid arthritis are examples. Solublezcytor11 receptor therapy would be beneficial to dampen or inhibit Bcells producing IgE in atopic diseases including asthma, allergy andatopic dermatitis where the production of IgE contributes to thepathogenesis of disease.

B cell malignancies may exhibit a loss of regulation by cytokines, suchas IL-TIF. The administration of the soluble zcytor11 receptors of thepresent invention following surgical resection or chemotherapy may beuseful to treat minimal residual disease in patients with B cellmalignancies. The loss of regulation may lead to sustain or increasedexpression of zcytor11. Thus creating a target for therapeuticmonoclonal antibodies targeting zcytor11 comprising receptors, such asthose described herein.

TABLE 5 Tissue # samples Tissue # samples adrenal gland 6 duodenum 1bladder 3 endometrium 5 brain 2 cancerous endometrium 1 brain meningioma1 gastric cancer 1 breast 1 esophagus 7 cancerous breast 4gastro-esophageal 1 normal breast adjacent 5 heart aorta 1 to cancerbronchus 3 heart left ventricle 4 colon 15 heart right ventricle 2cancerous colon 1 heart ventricle 1 normal colon adjacent 1 ileum 3 tocancer ulcerative colitis colon 1 kidney 15 cancerous kidney 1

TABLE 6 Tissue/Cell Line #samples Tissue/Cell Line #samples 293 1HBL-100 1 C32 1 Hs-294T 1 HaCat#1 1 Molt4 1 HaCat#2 1 RPMI 1 HaCat#3 1U-937 1 HaCat#4 1 A-375 1 WI-38 1 HCT-15 1 WI-38 + 2 um ionomycin 1HT-29 1 #1 WI-38 + 2 um ionomycin 1 MRC-5 1 #2 WI-38 + 5 um ionomycin 1RPT-1 1 #1 WI-38 + 5 um ionomycin 1 RPT-2 1 #2 Caco-2, 1 WM-115 1Caco-2, differentiated 1 A-431 1 DLD-1 1 WERI-Rb-1 1 HRE 1 HEL-92.1.7 1HRCE 1 HuH-7 1 MCF7 1 MV-4-11 1 PC-3 1 U-138 1 TF-1 1 CCRF-CEM 1 5637 1Y-79 1 143B 1 A-549 1 ME-180 1 EL-4 1 prostate epithelia 1 HeLa 229 1U-2 OS 1 HUT 78 1 T-47D 1 NCI-H69 1 Mg-63 1 SaOS2 1 Raji 1 USMC 1 U-373MG 1 UASMC 2 A-172 1 AoSMC 1 CRL-1964 1 UtSMC 1 CRL-1964 + butryic acid1 HepG2 1 HUVEC 1 HepG2-IL6 1 SK-Hep-1 1 NHEK#1 1 SK-Lu-1 1 NHEK#2 1Sk-MEL-2 1 NHEK#3 1 K562 1 NHEK#4 1 BeWo 1 ARPE-19 1 FHS74.Int 1 G-361 1HL-60 1 HISM 1 Malme 3M 1 3AsubE 1 FHC 1 INT407 1 HREC 1

TABLE 7 Tissue # samples Tissue # samples liver 10 lung 13 lymph node 1cancerous lung 2 lymphoma 4 normal lung adjacent to 1 cancer mammaryadenoma 1 muscle 3 mammary gland 3 neuroblastoma 1 melinorioma 1 omentum2 osteogenic sarcoma 2 ovary 6 pancreas 4 cancerous ovary 2 skin 5parotid 7 sarcoma 2 salivary gland 4

TABLE 8 Tissue # samples Tissue # samples small bowel 10 uterus 11spleen 3 uterine cancer 1 spleen lymphoma 1 thyroid 9 stomach 13 stomachcancer 1C. Tissue Distribution of Zcytor11 in Human Origene™ Tissue and HumanBlood Fractions MTC Panels Using RT-PCR

A panel of RNAs from human tissues, Human Origene™ Tissue and HumanBlood Fractions MTC Panels (Origene Technologies, Rockville, Md.; andClontech, Palo Alto, Calif.) was screened for zcytor11 expression usingRT-PCR. The panels contained 24 RNAs from various normal human tissuesat increasing concentrations as shown in Tables 9–10 below. The RT-PCRreactions were set up using oligos ZC37693 (SEQ ID NO:31) and ZC37449(SEQ ID NO:32), using the Advantage PCR kit (Clontech). Theamplification was carried out as follows: one cycle at 94° C. for 2min.; 35 cycles of 94° C. for 15 sec., 72° C. for 1.5 min; then 72° C.for 2 min.; followed by a 4° C. hold. 8 to 10 μl of the PCR reactionproduct was subjected to standard Agarose gel electrophoresis using a 4%agarose gel.

Using the Origene Panel, as shown in Table 9, the correct predicted cDNAfragment size (440 bp) was observed in all tissues except spleen,muscle, placenta, PBL, bone marrow and fetal brain. However, there washigh expression specifically in small intestine, colon, kidney, skin,lung, pancreas and liver. The weak expression of zcytor11 was alsoobserved in ovary, uterus, prostate, brain, heart, testis, stomach, andthyroid. Zcytor11 expression was not observed in the other tissues andcell lines tested in this panel. The expression pattern of zcytor11shows expression in specific tissues. One of skill in the art wouldrecognize that the polynucleotides, polypeptides, antibodies, andbinding partners of the present invention can be used as a diagnostic todetect such tissues, cancer, or cancer tissue in a biopsy, tissue, orhistologic sample, particularly in tissues where zcytor11 is expressed.Such diagnostic uses for the molecules of the present invention areknown in the art and described herein.

Using the Human Blood Fractions MTC Panel, as shown in Table 10, thecorrect predicted cDNA fragment size (440 bp) was observed inmononuclear cells, resting CD8+ cells, resting CD19+ cells and placenta.Zcytor11 expression was not observed in the other tissues and cell linestested in this panel, including activated CD8+ and CD19+ cells. Theexpression pattern of zcytor11 shows expression in specific tissues. Oneof skill in the art would recognize that the polynucleotides,polypeptides, antibodies, and binding partners of the present inventioncan be used as a diagnostic to detect such tissues, cancer, or cancertissue in a biopsy, tissue, or histologic sample, particularly intissues where zcytor11 is expressed. Such diagnostic uses for themolecules of the present invention are known in the art and describedherein.

TABLE 9 Tissue 1 pg cDNA 10 pg cDNA 100 pg cDNA 1 ng cDNA Brain X HeartX Kidney X X Spleen Liver X X Colon X X Lung X X Small X X X IntestineMuscle Stomach X X Testis X X X Placenta X Salivary X Gland Thyroid X XGland Adrenal X X Gland Pancreas X X X X Ovary X Uterus X Prostate XSkin X X PBL Bone Marrow Fetal Brain Fetal Liver X X X

TABLE 10 1 ng cDNA Expression Mononuclear cells X Resting CD8+ cells XResting CD4+ cells Resting CD14+ cells Resting CD19+ cells X ActivatedCD19+ cells Activated mononuclear cells Activated CD4+ cells ActivatedCD8+ cells Human Placenta X No template control Zcytor11 cDNA XD. Tissue Distribution of Zcytor11 in Human Primary Immune Cell andImmune Cell Lines Using RT-PCR

A panel of RNAs from primary human immune cell populations and humanimmune cell lines was screened for zcytor11 expression using RT-PCR. Thepanels were made in house and contained 24 RNAs from various resting andactivated cell populations and cell lines as shown in Table 11 below.All primary immune cell populations were isolated from the blood ofseveral anonymous donors. Various immune cell subsets (CD4+, CD8+,CD14+, CD19+, and CD56+) were then isolated using Microbeads and theMagnetic Cell Separation System from Miltenyi Biotec. RNA was preparedfrom the CD19+ and CD56+ populations in their resting state using anRNeasy Midiprep™ Kit (Qiagen, Valencia, Calif.) as per manufacturer'sinstruction. The CD4+, and CD8+ populations were activated using 200ng/ml plate-bound anti-CD3 antibody and 5 μg/ml soluble anti-CD28antibody and cells were collected for RNA isolation at 0, 4 and 16hours. The CD19+ samples were isolated from human tonsil and activatedwith 0.5 μg/ml Ionomycin and 10 ng/ml PMA. Cells were then collected at0, 4 hours and 24 hours and RNA isolated. Human CD14+ monocytes wereactivated with either 0.1 μg/ml LPS or 1.0 μg/ml LPS for 20 hours.Resting and activated cells were then collected and RNA isolated. Inaddition, RNA was isolated from resting and activated (10.0 μg/ml LPS)human monocyte cell lines HL-60, THP-1 and U937. Also, resting Raji,Ramos, Daudi, and Jurkat RNA's were tested.

The RT-PCR reactions used the Superscript One-Step RT-PCR System withPlatinum Taq. Each 25 μl reaction consisted of the following: 12.5 μl of2×Reaction Buffer, 0.5 μl (20 pmol.μl) ZC14,666 (SEQ ID NO:11), 0.5 μl(20 pmol/μl) ZC14,742 (SEQ ID NO:12), 0.4 μl RT/Taq polymerase mix, 10μl RNase-free water, 1.0 μl template RNA (100 ng/μl). (LifeTechnologies, Gaithersburg, Md.). The amplification was carried out asfollows: one cycle at 50° for 30 minutes followed by 35 cycles of 94°,30 seconds; 52°, 30 seconds; 72°, 60 seconds; then ended with a finalextension at 72° for 7 minutes. 8 to 10 μl of the PCR reaction productwas subjected to standard Agarose gel electrophoresis using a 2% agarosegel. The correct predicted cDNA fragment size was observed in restingCD19+ B cells and much less in the activated CD19+ B cells, resting CD8+T cells, CD56+ NK cells and activated CD14+ monocytes. Cell linesshowing expression of zcytor11 were Jurkat, activated THP-1 andactivated HL-60. Zcytor11 expression was not observed in the othertissues and cell lines tested in this panel. These results demonstratethe expression of zcytor11 in several immune cell populations and immunecell lines.

TABLE 11 Tissue # samples Tissue # samples CD19+ from resting PBMCs 1CD14+ 0.1 μg/ml 1 LPS CD19+ resting from tonsil 1 CD14+ 1.0 μg/ml 1 LPSCD19+ from tonsil - 4 hr 1 Raji 1 activation CD19+ from tonsil - 16 hr 1Ramos 1 activation CD4+ Resting 1 Daudi 1 CD4+ 4 hr Activation 1 Jurkat1 CD4+ 16 hr Activation 1 U937 1 CD8+ Resting 1 Activated U937 1 CD8+ 4hr Activation 1 THP-1 1 CD8+ 16 hr Activation 1 Activated THP-1 1 CD56+Resting 1 HL-60 1 CD14+ Resting 1 Activated HL-60 1

EXAMPLE 16 Construction of BaF3 Cells Expressing the CRF2-4 Receptor(BaF3/CRF2-4 Cells) and BaF3 Cells Expressing the CRF2-4 Receptor withthe zcytor11 Receptor (BaF3/CRF2-4/zcytor11 Cells)

BaF3 cells expressing the full-length CFR2-4 receptor were constructed,using 30 μg of a CFR2-4 expression vector, described below. The BaF3cells expressing the CFR2-4 receptor were designated as BaF3/CFR2-4.These cells were used as a control, and were further transfected withfull-length zcytor11 receptor (U.S. Pat. No. 5,965,704) and used toconstruct a screen for IL-TIF activity as described below.

A. Construction of BaF3 Cells Expressing the CRF2-4 Receptor

The full-length cDNA sequence of CRF2-4 (Genbank Accession No. Z17227)was isolated from a Daudi cell line cDNA library, and then cloned intoan expression vector pZP7P.

BaF3, an interleukin-3 (IL-3) dependent pre-lymphoid cell line derivedfrom murine bone marrow (Palacios and Steinmetz, Cell 41: 727–734, 1985;Mathey-Prevot et al., Mol. Cell. Biol. 6: 4133–4135, 1986), wasmaintained in complete media (RPMI medium (JRH Bioscience Inc., Lenexa,Kans.) supplemented with 10% heat-inactivated fetal calf serum, 2 ng/mlmurine IL-3 (mIL-3) (R & D, Minneapolis, Minn.), 2 mM L-glutaMax-1™(Gibco BRL), 1 mM Sodium Pyruvate (Gibco BRL), and PSN antibiotics(GIBCO BRL)). Prior to electroporation, CRF2-4/pZP7P was prepared andpurified using a Qiagen Maxi Prep kit (Qiagen) as per manufacturer'sinstructions. For electroporation, BaF3 cells were washed once inserum-free RPMI media and then resuspended in serum-free RPMI media at acell density of 10⁷ cells/ml. One ml of resuspended BaF3 cells was mixedwith 30 μg of the CRF2-4/pZP7P plasmid DNA and transferred to separatedisposable electroporation chambers (GIBCO BRL). Following a 15-minuteincubation at room temperature the cells were given two serial shocks(800 lFad/300 V.; 1180 lFad/300 V.) delivered by an electroporationapparatus (CELL-PORATOR™; GIBCO BRL). After a 5-minute recovery time,the electroporated cells were transferred to 50 ml of complete media andplaced in an incubator for 15–24 hours (37° C., 5% CO₂). The cells werethen spun down and resuspended in 50 ml of complete media containing 2μg/ml puromycin in a T-162 flask to isolate the puromycin-resistantpool. Pools of the transfected BaF3 cells, hereinafter calledBaF3/CRF2-4 cells, were assayed for signaling capability as describedbelow. Moreover these cells were further transfected with zcytor11receptor as described below.

B. Construction of BaF3 Cells Expressing CRF2-4 and zcytor11 Receptors

BaF3/CRF2-4 cells expressing the full-length zcytor11 receptor wereconstructed as per Example 5A above, using 30 μg of the zcytor11expression vector, described in Example 6 above. Following recovery,transfectants were selected using 200 μg/ml zeocin and 2 μg/mlpuromycin. The BaF3/CRF2-4 cells expressing the zcytor11 receptor weredesignated as BaF3/CRF2-4/zcytor11 cells. These cells were used toscreen for IL-TIF activity as well as zcytor16 antagonist activitydescribed IN Example 17.

EXAMPLE 17 Screening for CRF2-4Zcytor11-Fc Activity UsingBaF3/CRF2-4/zcytor11 Cells in an Alamar Blue Proliferation Assay

BaF3/CRF2-4/zcytor11 cells (Example 16) were spun down and washed in PBS2 times to ensure the removal of the mIL-3, and then spun a third timeand resuspended in the complete media, (RPMI 1640, 10% FBS, 1% GlutaMAX,1% Sodium Pyruvate) described in Example 16 above, but without mIL-3(hereinafter referred to as “mIL-3 free media”). Cells were then countedin a hemocytometer. Cells were plated in a 96-well format at 5000 cellsper well in a volume of 50 μl per well using the mIL-3 free media.

IL-TIF protein was diluted to 200 pg/ml in mIL-3 free media and also inCRF2-4/zcytor11-Fc conditioned media at a concentration of approximately0.4 ug/ml that was made from transfected BHK cells (Example 7). TheCRF2-4/zcytor11-Fc CM was diluted into the mIL-3 free/IL-TIF media byserial 1:2 dilutions down all 8 rows on the 96-well plate, leaving avolume of 50 ul in each well. This was then added to the 50 ul of cells,for a final IL-TIF concentration of 100 pg/ml in all wells, and finalCRF2-4/zcytor11-Fc concentrations of approximately 200, 100, 50, 25,12.5, 6.25, 3.1 and 1.6 ng/ml, and a total assay volume of 100 μl. Theassay plates were incubated at 37° C., 5% CO₂ for 4 days at which timeAlamar Blue (Accumed, Chicago, Ill.) was added at 20 μl/well. Plateswere again incubated at 37° C., 5% CO₂ for 24 hours. Alamar Blue gives afluourometric readout based on number of live cells, and is thus adirect measurement of cell proliferation in comparison to a negativecontrol. Plates were read on the Wallac Victor 2 1420 Multilabel Counter(Wallac, Turku, Finland) at wavelengths 530 (Excitation) and 590(Emmssion).

Results confirmed a dose-dependant inhibition by CRF2-4/zcytor11-Fc ofthe proliferative effect of IL-TIF on BaF3/CRF2-4/zcytor11 cells. IL-TIFalone stimulated the cells 30-fold over background. CRF2-4/zcytor11-Fccompletely inhibited that proliferation at concentrations of 25–200ng/ml, partially inhibited proliferation at 3.1–12.5 ng/ml, andinhibition was barely detectable at 1.6 ng/ml. The same setup was donewith mIL-TIF, and generated similar results.

EXAMPLE 18 Flow Cytometry Analysis of Baf3-Transfectants Expressingzcytor11 Alone CRF2-4 Alone, zcytor11/CRF-4, or zcytor11/pDIRS1

BaF3 cells transfected with zcytor11 alone, CRF2-4 alone,zcytor11/CRF2-4, or zcytor11/pDIRS1 were generated with each respectivecytokine receptor, as described (Example 16). Briefly, 30 ug ofzcytor11/pZP7Z were transfected into BaF3 cells using electroporation,and the stable transfectants (BaF3/zcytor11) were selected with 200μg/ml zeocin. Similarly BaF3 cells transfected with CRF2-4/pZP7P(BaF3/CRF2-4) were selected with 2 μg/ml puromycin. Subsequently, 30 ugof CRF2-4/pZP7P were transfected into BaF3/zcytor11 cells usingelectroporation, and the stable cell line (BaF3/zcytor11/CRF2-4) wasselected with 200 μg/ml zeocin and 2 μg/ml puromycin. Similarly, 30 ugof pDIRS1/pZP7P were transfected into BaF3/zcytor11 cells usingelectroporation, and the stable cell line (BaF3/zcytor11/pDIRS1) wasselected with 200 μg/ml zeocin and 2 ug/ml puromycin. The BHKtransfectants were generated using the same expression vectors of eitherzcytor11, CRF2-4, or pDIRS1 for BaF3 transfectants. DNA was transfectedinto BHK cells using Lipofectamine™ (Gibco BRL, Gaitersburg, Md.) as permanufacturer's instructions, the selection was started 48-hrpost-transfection following the same protocol for BaF3 selection.

The biotinylation of human IL-TIF-CEE (Example 12) protein is done asfollows: 1.6 ul 10% Tween20, 50 ul 1M boric acid (pH 8.5), and 42 ul of0.9 mg/ml EZ-link Sulfo-NHS-LC-biotin (Pierce, Rockford, Ill.) dissolvedin DMSO were added into 100 ul of 2.2 mg/ml IL-TIF-CEE. After 1 hrincubation at room temperature, the reaction was quenched with 10 ul of2M glycine for 10 minutes.

To test the binding properties of the IL-TIF ligand to several potentialreceptor components, BaF3 and BHK cells were transfected with expressionplasmids including zcytor11 alone, CRF2-4 alone (Genbank Accession No.Z17227), zcytor11 (SEQ ID NO:1) and CRF2-4, or zcytoR11 and pDIRS1 (WIPOPublication WO99/46379, Schering Corporation, 1999), as described above.Untransfected BaF3 and BHK cells were included as controls. Cells wereresuspended in FACS wash buffer (WB: PBS/1% BSA, supplemented with 3%human Ultraserum (Gemini BioProducts, Calabasas, Calif.)) counted and1×10⁶ of each type were aliquoted into 5 ml polystyrene tubes. Cellswere washed and pelleted, then incubated for 20 min on ice with 100 μlof WB only, or WB plus 10 μg/ml or 1 μg/ml biotinylated zcyto10 protein.Cells were washed with 1.5 ml WB and pelleted, then incubated in 100 μlof 2.5 μg/ml phycoerthyrin-conjugated streptavidin (PE-SA, PharMingen,San Diego, Calif.) for another 20 min on ice. Cells were washed asbefore, resuspended in 0.4 ml of WB and analyzed on a FACScan usingCellQuest software (Becton Dickinson, Mountain View, Calif.).

The biotin-IL-TIF bound in a dose-dependent fashion to all 3 of thetransfected BaF3 cell lines containing zcytor11 (i.e. zcytor11transfected alone, or in combination with CRF2-4 or DIRS1), but not tothe parental line or to the BaF3×CRF2-4 transfectant. The same resultswere obtained with the corresponding BHK transfectants.

From the foregoing, it will be appreciated that, although specificembodiments of the invention have been described herein for purposes ofillustration, various modifications may be made without deviating fromthe spirit and scope of the invention. Accordingly, the invention is notlimited except as by the appended claims.

1. A method for inhibiting IL-TIF-induced proliferation of neutrophilsor platelets comprising culturing bone marrow or peripheral blood cellswith a composition comprising an amount of soluble cytokine receptorcomprising SEQ ID NO:3 sufficient to reduce proliferation of theneutrophils or platelets in the bone marrow or peripheral blood cells ascompared to bone marrow or peripheral blood cells cultured in theabsence of the soluble cytokine receptor.
 2. The method of claim 1,wherein the soluble cytokine receptor further comprises a soluble CRF2-4polypeptide (SEQ ID NO:33).
 3. An isolated soluble cytokine receptorpolypeptide complex comprising more than one soluble receptor subunit,wherein at least one of the soluble receptor subunits comprises thesequence of amino acid residues shown in SEQ ID NO:3, and wherein asecond soluble receptor subunit comprises the soluble CRF2-4 polypeptide(SEQ ID NO:33, and wherein the soluble cytokine receptor polypeptidebinds IL-TIF or antagonizes IL-TIF activity.
 4. An isolated solublecytokine receptor polypeptide complex consisting of two soluble receptorsubunits, wherein at least one of the soluble receptor subunits consistsof the sequence of amino acid residues shown in SEQ ID NO:3, and whereina second soluble receptor subunit consists of soluble CRF2-4 polypeptide(SEQ ID NO:33), and wherein the soluble cytokine receptor polypeptidebinds IL-TIF or antagonizes IL-TIF activity.
 5. An isolated polypeptideaccording to claim 3, wherein the soluble cytokine receptor polypeptidecomprises a heterodimeric receptor complex.
 6. The isolated polypeptideaccording to claim 3, wherein the soluble cytokine receptor polypeptidecomprises a multimeric receptor complex.
 7. An isolated polypeptideaccording to claim 3, wherein the soluble cytokine receptor polypeptidefurther comprises an affinity tag, label, chemical moiety, toxin,biotin/avidin label, radionuclide, enzyme, substrate, cofactor,inhibitor, fluorescent marker, chemiluminescent marker, cytotoxicmolecule or an immunoglobulin Fc domain.
 8. An isolated polypeptideaccording to claim 4, wherein the soluble cytokine receptor polypeptidecomprises a heterodimeric receptor receptor complex.
 9. An isolatedpolypeptide according to claim 4, wherein the soluble cytokine receptorpolypeptide further comprises an affinity tag, label, chemical moiety,toxin, biotin/avidin label, radionuclide, enzyme, substrate, cofactor,inhibitor, fluorescent marker, chemiluminescent marker, cytotoxicmolecule or an immunoglobulin Fc domain.